Shallow Thoughts

Learning about Firefox 3 extensions

Oops! Right after I posted that last entry, I discovered that my little kitfox extension wasn't working as well as I'd thought. And the more I hacked it, the less well it worked, and the more I discovered was missing, like a chrome.manifest file (which firefox 2 hadn't seemed to need).

Eventually some very helpful folks on #extdev pointed me to Ted Mielczarek's excellent Extension Wizard. Give it some details about your extension (its name and version, your name, and a couple things you might want like a toolbar button, a prefs panel and a context menu) and it generates a zipped directory containing a bare bones extension, even including niceties like internationalized strings.

Even better, your new extension skeleton includes a readme that tells you how to leave the extension expanded while you work on it. That's quite a bit easier than building the XPI file and installing it each time.

So kitfox has a 0.3 version (in the unlikely event that anybody besides me wants it).

There's a project called fizzypop to develop and extend useful Mozilla dev tools like the Extension Wizard ... watch that space for more details.

Tags: mozilla, firefox, open source
[ 20:12 Jul 04, 2008    More tech/web | permalink to this entry ]

Making Firefox 3 livable

I finally broke down and spent the time to get Firefox 3 working properly for me ... meaning, mostly, finding replacement extensions for the bare minimum of what I need in a browser: control over cookies (specifically, enabling/disabling them for specific sites), flashblock, and blocking of animated images. I'd downloaded extensions for all those a few weeks ago, but I found that although Firefox 3.0 said the FF3 extensions were active, and Firefox 2 said the old ones were, neither set actually worked.

I decided to start from scratch: remove all extensions -- rm -rf .mozilla/firefox/extensions/* .mozilla/firefox/extensions.* plus apt-get remove firefox-2-dom-inspector -- then install a new set of Firefox 3 add-ons.

After much hunting (I sure wish addons.mozilla.org would offer a way to limit the view to only extensions that work with Firefox 3! Combing through 15 pages of extensions looking for the handful that will actually install gets old fast) I found the replacements I needed: CS Lite for the cookie controls, a newer Flashblock, and Custom Toolbar Buttons as a stopgap for image animation (though I suspect updating anidisable will be a better solution in the long run). This time, with the old firefox 2 extensions purged, the new ones took hold and worked.

I also added a nice extension called OpenBook that fixes the horrible Firefox "Add bookmark" dialog. You know: the one that has two nearly identical dropdown category menus side by side, with the bigger one giving you only a tiny subset of your bookmark categories, and the smaller one being the real one. The one that doesn't offer a space for keyword, so to set up a bookmarklet you have to Add Bookmark, OK, Organize Bookmarks, find the bookmark you just added, Ctrl-I to get the Bookmark info dialog, and finally you can add your keyword. OpenBook gives you a dialog where you can set the keyword to begin with, and it only gives you one menu to list categories so you aren't constantly tempted to click on the wrong one.

Now for the urlbar -- that new firefox 3 "smarter" urlbar that slows down typing in the middle of a word so it can pop up a big fancy window full of guesses (all wrong) about where I might be trying to go. Actually, even if the guesses were right, it wouldn't help, because I'd have to stop typing, search the list visually, then if one of the suggestions was right, move my hand to the mouse or the arrow keys to choose that suggestion. That takes way longer than just typing the url.

But I guess I don't mind unhelpful suggestions popping up as long as it doesn't mess up focus (preventing me from clicking or tabbing to other apps on my screen) or slow down typing. Firefox 3 seems to be handling the focus issue better than firefox 2 did, but the slowdown was quite noticeable on the poor old laptop. So I wanted a way to disable the behavior. A little googling revealed that the Firefox crew immodestly calls their new urlbar the "awesomebar", which aside from giggle factor also proves quite useful in googling: a search on firefox disable awesomebar reveals that I'm not the only one who doesn't like it, and got me several preferences I could tweak in about:config plus a couple of extensions to turn it off entirely. I won't try to summarize, since the best settings depend on your machine's spec, plus personal preference.

Making progress! Now the only issue was getting my urlbar tweaks working, so that typing <Ctrl-Return> after typing a URL opened the URL in a new tab instead of tacking on various silly extensions (oh, yes, of course I wanted to go to http://www.firefox disable awesomebar.com rather than googling for those terms in a new tab). Fortunately, it turned out that the javascript that runs the urlbar has changed very little since firefox 2, and I hardly needed to change anything to get my kitfox extension (v. 0.2) working in Firefox 3.

Only one more issue: this blog. The CSS that handles the right sidebar wasn't displaying right. Seems that Firefox 2 has changed something about its interpretation of CSS, so it was floating the right sidebar way down to the bottom of the page below the last content line. Eventually (after adding firefox-3.0-dom-inspector, another extension that had stopped working in the transition) I discovered the problem: the #content was set to width: 77% while the #rightsidebar's left-margin was at 76%. Apparently Firefox 2 rounded up as needed, whereas Firefox 3 just ignores the left-margin if it would overlap the content, and then floats the sidebar anywhere it thinks it can fit it. Fixing those percentages helped quite a bit, and I added an overflow-x: hidden (on a tip from a helpful person in #firefox) so that wide calendar doesn't hurt layout for narrow windows. I think it's working now ... any readers having problems with the layout in any browser, by all means let me know.

Tags: mozilla, firefox, user interface, css, bookmarklets
[ 11:04 Jul 04, 2008    More tech/web | permalink to this entry ]

Making Firefox default to Portrait printing

I discovered a handy tip for Linux Firefox' printing Page Setup today.

Normal web page printing uses "Portrait" mode: you read the page with the paper oriented so that it's taller than it is wide.

Once a week, I need to print a form from a club web site to bring to the meetings. It's a table that's much wider than it is tall, so I want to print it that way: in "Landscape" mode.

In Firefox 2 (at least on Linux), you can't do that from the Print dialog -- there's no Portrait/Landscape option. So you have to use a separate dialog, Page Setup, following these steps:

1. Run Page Setup
2. Change Portrait to Landscape
3. Click OK
4. Print (bring up the Print dialog and click OK)
5. Run Page Setup
6. Change Landscape to Portrait
7. Click OK

Kind of a lot of steps just to print one landscape page! But if you forget, the next page you print from Firefox will be printed in Landscape mode and will take twice as many pages as it should (if you don't notice what's happening and dive for the printer's OFF switch in time, that being the only way to cancel a printing job once it hits the printer).

This morning, it finally occurred to me that Firefox was storing this setting somehow, most likely in prefs.js. If I could find the setting and force it in user.js (which takes precedence over prefs.js and is not updated by Firefox), I could make Firefox set itself back to Portrait every time it starts up. (prefs.js and user.js are both generally found in $HOME/.mozilla/firefox/).

Some greppery-pokery revealed the solution. I needed only to add a line in user.js that looks like this:

user_pref("print.printer_CUPS/Epson.print_orientation", 0);

and presto! my problem was solved.

Oddly, it's set separately for every printer you have defined, even though there's no way to set one printer to Landscape while another one is still on Portrait (the Page Setup dialog is global, and applies to every printer Firefox knows about). "Epson" is the CUPS name of my primary printer; replace that with your printer's name (as set in CUPS), and add a similar line for each printer you have. For the printers I've used, 0 is Portrait and 1 is Landscape, but you can verify that by typing:

grep orientation prefs.js | grep name

That command will also help you if you're not sure what printers you have defined, or you don't use CUPS but want to try this under a different print spooler. (Don't be misled by all the orientation prefs with "tmp" in the name.)

As a minor digression, there's actually a secret pref that's supposed to give another way around the problem:

user_pref("print.whileInPrintPreview", true);

This lets you do all your printing from the Print Preview window, which offers its own Portrait and Landscape buttons. That would be a nice solution. Alas, the Portrait and Landscape buttons in that dialog currently don't work, and since this preference is undocumented and unmaintained, filing more bugs isn't likely to help.

(I should mention that this all pertains to Firefox 2. I haven't switched to Firefox 3 yet, so I don't know the state of its printing UI, or whether this preference is either helpful or effective there.)

Tags: mozilla, firefox, printing, tips
[ 20:07 Jun 12, 2008    More tech/web | permalink to this entry ]

Wrapping plaintext files in Firefox

A friend pointed me to a story she'd written. It was online as a .txt file. Unfortunately, it had no line breaks, and Firefox presented it with a horizontal scrollbar and no option to wrap the text to fit in the browser window.

But I was sure that was a long-solved problem -- surely there must be a userContent.css rule or a bookmarklet to handle text with long lines. The trick was to come up with the right Google query. Like this one: firefox OR mozilla wrap text userContent OR bookmarklet

I settled on the simple CSS rule from Tero Karvinen's page on Making preformated <pre> text wrap in CSS3, Mozilla, Opera and IE:

pre {
 white-space: -moz-pre-wrap !important;
}

Add it to chrome/userContent.css and you're done.

But some people might prefer not to apply the rule to all text. If you'd prefer a rule that can be applied at will, a bookmarklet would be better. Like the word wrap bookmarklet from Return of the Sasquatch or the one from Jesse Ruderman's Bookmarklets for Zapping Annoyances collection.

Tags: tech, web, mozilla, firefox, css, bookmarklets
[ 10:47 Apr 08, 2008    More tech/web | permalink to this entry ]

Firefox, caching, and fast Back/Forward buttons

I remember a few years ago the Mozilla folks were making a lot of noise about the "blazingly fast Back/Forward" that was coming up in the (then) next version of Firefox. The idea was that the layout engine was going to remember how the page was laid out (technically, there would be a "frame cache" as opposed to the normal cache which only remembers the HTML of the page). So when you click the Back button, Firefox would remember everything it knew about that page -- it wouldn't have to parse the HTML again or figure out how to lay out all those tables and images, it would just instantly display what the page looked like last time.

Time passed ... and Back/Forward didn't get faster. In fact, they got a lot slower. The "Blazingly Fast Back" code did get checked in (here's how to enable it) but somehow it never seemed to make any difference.

The problem, it turns out, is that the landing of bug 101832 added code to respect a couple of HTTP Cache-Control header settings, no-store and no-cache. There's also a third cache control header, must-revalidate, which is similar (the difference among the three settings is fairly subtle, and Firefox seems to treat them pretty much the same way).

Translated, that means that web servers, when they send you a page, can send some information along with the page that asks the browser "Please don't keep a local copy of this page -- any time you want it again, go back to the web and get a new copy."

There are pages for which this makes sense. Consider a secure bank site. You log in, you do your banking, you view your balance and other details, you log out and go to lunch ... then someone else comes by and clicks Back on your browser and can now see all those bank pages you were just viewing. That's why banks like to set no-cache headers.

But those are secure pages (https, not http). There are probably reasons for some non-secure pages to use no-cache or no-store ... um ... I can't think of any offhand, but I'm sure there are some.

But for most pages it's just silly. If I click Back, why wouldn't I want to go back to the exact same page I was just looking at? Why would I want to wait for it to reload everything from the server?

The problem is that modern Content Management Systems (CMSes) almost always set one or more of these headers. Consider the Linux.conf.au site. Linx.conf.au is one of the most clueful, geeky conferences around. Yet the software running their site sets

  Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
  Pragma: no-cache

on every page. I'm sure this isn't intentional -- it makes no sense for a bunch of basically static pages showing information about a conference several months away. Drupal, the CMS used by LinuxChix sets Cache-Control: must-revalidate -- again, pointless. All it does is make you afraid to click on links because then if you want to go Back it'll take forever. (I asked some Drupal folks about this and they said it could be changed with drupal_set_header).

(By the way, you can check the http headers on any page with: wget -S -O /dev/null http://... or, if you have curl, curl --head http://...)

Here's an excellent summary of the options in an Opera developer's blog, explaining why the way Firefox handle caching is not only unfriendly to the user, but also wrong according to the specs. (Darn it, reading sensible articles like that make me wish I wasn't so deeply invested in Mozilla technology -- Opera cares so much more about the user experience.)

But, short of a switch to Opera, how could I fix it on my end? Google wasn't any help, but I figured that this must be a reported Mozilla bug, so I turned to Bugzilla and found quite a lot. Here's the scoop. First, the code to respect the cache settings (slowing down Back/Forward) was apparently added in response to bug 101832. People quickly noticed the performance problem, and filed 112564. (This was back in late 2001.) There was a long debate, but in the end, a fix was checked in which allowed no-cache http (non-secure) sites to cache and get a fast Back/Forward. This didn't help no-store and must-revalidate sites, which were still just as slow as ever.

Then a few months later, bug 135289 changed this code around quite a bit. I'm still getting my head around the code involved in the two bugs, but I think this update didn't change the basic rules governing which pages get revalidated.

(Warning: geekage alert for next two paragraphs. Use this fix at your own risk, etc.)

Unfortunately, it looks like the only way to fix this is in the C++ code. For folks not afraid of building Firefox, the code lives in nsDocShell::ShouldDiscardLayoutState and controls the no-cache and no-store directives. In nsDocShell::ShouldDiscardLayoutState (currently lie 8224, but don't count on it), the final line is:

    return (noStore || (noCache && securityInfo));

Change that to

    return ((noStore || noCache) && securityInfo);

and Back/Forward will get instantly faster, while still preserving security for https. (If you don't care about that security issue and want pages to cache no matter what, just replace the whole function with return PR_FALSE; )

The must-validate setting is handled in a completely different place, in nsHttpChannel. However, for some reason, fixing nsDocShell also fixes Drupal pages which set only must-validate. I don't quite understand why yet. More study required. (End geekage.)

Any Mozilla folks are welcome to tell me why I shouldn't be doing this, or if there's a better way (especially if it's possible in a way that would work from an extension or preference). I'd also be interested in from Drupal or other CMS folks defending why so many CMSes destroy the user experience like this. But please first read the Opera article referenced above, so that you understand why I and so many other users have complained about it. I'm happy to share any comments I receive (let me know if you want your comments to be public or not).

Tags: tech, web, mozilla, firefox, performance
[ 19:32 Oct 20, 2007    More tech/web | permalink to this entry ]

Make Amazon pages narrow enough to read

I like buying from Amazon, but it's gotten a lot more difficult since they changed their web page design to assume super-wide browser windows. On the browser sizes I tend to use, even if I scroll right I can't read the reviews of books, because the content itself is wider than my browser window. Really, what's up with the current craze of insisting that everyone upgrade their screen sizes then run browser windows maximized?

(I'd give a lot for a browser that had the concept of "just show me the page in the space I have". Opera has made some progress on this and if they got it really working it might even entice me away from Firefox, despite my preference for open source and my investment in Mozilla technology ... but so far it isn't better enough to justify a switch.)

I keep meaning to try the greasemonkey extension, but still haven't gotten around to it. Today, I had a little time, so I googled to see if anyone had already written a greasemonkey script to make Amazon readable. I couldn't find one, but I did find a page from last October trying to fix a similar problem on another website, which mentioned difficulties in keeping scripts working under greasemonkey, and offered a Javascript bookmarklet with similar functionality.

Now we're talking! A bookmarklet sounds a lot simpler and more secure than learning how to program Greasemonkey. So I grabbed the bookmarklet, a copy of an Amazon page, and my trusty DOM Inspector window and set about figuring out how to make Amazon fit in my window.

It didn't take long to realize that what I needed was CSS, not Javascript. Which is potentially a lot easier: "all" I needed to do was find the right CSS rules to put in userContent.css. "All" is in quotes because getting CSS to do anything is seldom a trivial task.

But after way too much fiddling, I did finally come up with a rule to get Amazon's Editorial Reviews to fit. Put this in chrome/userContent.css inside your Firefox profile directory (if you don't know where your profile directory is, search your disk for a file called prefs.js):

div#productDescription div.content { max-width: 90% !important; }

You can replace that 90% with a pixel measurement, like 770px, or with a different percentage.

I spent quite a long time trying to get the user reviews (a table with two columns) to fit as well, without success. I was trying things like:

#customerReviews > div.content > table > tbody > tr > td { max-width: 300px; min-width: 10px !important; }
div#customerReviews > div.content > table { margin-right: 110px !important; }

but nothing worked, and some of it (like the latter of those two lines) actually interfered with the div.content rule for reasons I still don't understand. (If any of you CSS gurus want to enlighten me, or suggest a better or more complete solution, or solutions that work with other web pages, I'm all ears!)

I'll try for a more complete solution some other time, but for now, I'm spending my July 4th celebrating my independance from Amazon's idea of the one true browser width.

Tags: tech, web, css, mozilla, firefox
[ 20:01 Jul 04, 2007    More tech/web | permalink to this entry ]

A Quartet of Workarounds

I upgraded my laptop's Ubuntu partition from Edgy to Feisty. Debian Etch works well, but it's just too old and I can't build software like GIMP that insists on depending on cutting-edge libraries.

But Feisty is cutting edge in other ways, so it's been a week of workarounds, in two areas: Firefox and the kernel. I'll start with Firefox.

Firefox crashes playing flash

First, the way Ubuntu's Firefox crashes when running Flash. I run flashblock, fortunately, so I've been able to browse the web just fine as long as I don't click on a flashblock button. But I like being able to view the occasional youtube video, and flash 7 has worked fine for me on every distro except Ubuntu. I first saw the problem on Edgy, and upgrading to Feisty didn't cure the problem.

But it wasn't their Firefox build; my own "kitfox" firefox build crashed as well. And it wasn't their flash installation; I've never had any luck with either their adobe flash installer nor their opensource libswfdec, so I'm running the same old flash 7 plug-in that I've used all along for other distros.

To find out what was really happening, I ran Firefox from the commandline, then went to a flash page. It turned out it was triggering an X error:

The error was: 'BadMatch (invalid parameter attributes)'.
(Details: serial 104 error_code 8 request_code 145 minor_code 3)

That gave me something to search for. It turns out there's a longstanding Ubuntu bug, 14911 filed on this issue, with several workarounds. Setting the environment variable XLIB_SKIP_ARGB_VISUALS to 1 fixed the problem, but, reading farther in the bug, I saw that the real problem was that Ubuntu's installer had, for some strange reason, configured my X to use 16 bit color instead of 24. Apparently this is pretty common, and due to some bug involving X's and Mozilla's or Flash's handling of transparency, this causes flash to crash Mozilla.

So the solution is very simple. Edit /etc/X11/xorg.conf, look for the DefaultDepth line, and if it's 16, that's your problem. Change it to 24, restart X and see if flash works. It worked for me!

Eliminating Firefox's saved session pester dialog

While I was fiddling with Firefox, Dave started swearing. "Why does Firefox always make me go through this dialog about restoring the last session? Is there a way to turn that off?"

Sure enough, there's no exposed preference for this, so I poked around about:config, searched for browser and found browser.sessionstore.resume_from_crash. Doubleclick that line to change it to false and you'll have no more pesky dialog.

For more options related to session store, check the Mozillazine Session Restore page.

Kernel: runaway kacpid

Alas, having upgraded to Feisty expressly so that I could build cutting-edge programs like GIMP, I discovered that I couldn't build anything at all. Anything that uses heavy CPU for more than a minute or two triggers a kernel daemon, kacpid, to grab most of the CPU for itself. Being part of the kernel (even though it has a process ID), kacpi is unkillable, and prevents the machine from shutting down, so once this happens the only solution is to pull the power plug.

This has actually been a longstanding Ubuntu problem (bug 75174) but it used to be that disabling acpid would stop kacpid from running away, and with feisty, that no longer helps. The bug is also kernel.org bug 8274.

The Ubuntu bug suggested that disabling cpufreq solved it for one person. Apparently the only way to do that is to build a new kernel. There followed a long session of attempted kernel building. It was tricky because of course I couldn't build on the target machine (inability to build being the problem I was trying to solve), and even if I built on my desktop machine, a large rsync of the modules directory would trigger a runaway kacpi. In the end, building a standalone kernel with no modules was the only option.

But turning off cpufreq didn't help, nor did any of the other obvious acpi options. The only option which stops kacpid is to disable acpi altogether, and use apm. I'm sorry to lose hibernate, and temperature monitoring, but that appears to be my only option with modern kernels. Sigh.

Kernel: Hangs for 2 minutes at boot time initializing sound card

While Dave and I were madly trying to find a set of config options to build a 2.6.21 that would boot on a Vaio (he was helping out with his SR33 laptop, starting from a different set of config options) we both hit, at about the same time, an odd bug: partway through boot, the kernel would initialize the USB memory stick reader:

sd 0:0:0:0: Attached scsi removable disk sda
sd 0:0:0:0: Attached scsi generic sg0 type 0

and then it would hang, for a long time. Two minutes, as it turned out. And the messages after that were pretty random: sometimes related to the sound card, sometimes to the network, sometimes ... GConf?! (What on earth is GConf doing in a kernel boot sequence?) We tried disabling various options to try to pin down the culprit: what was causing that two minute hang?

We eventually narrowed the blame to the sound card (which is a Yamaha, using the ymfpci driver). And that was enough information for google to find this Linux Kernel Mailing List thread. Apparently the sound maintainer decided, for some reason, to make the ymfpci driver depend on an external firmware file ... and then didn't include the firmware file, nor is it included in the alsa-firmware package he references in that message. Lovely. I'm still a little puzzled about the timeout: the post does not explain why, if a firmware file isn't found on the disk, waiting for two minutes is likely to make one magically appear.

Apparently it will be fixed in 2.6.22, which isn't much help for anyone who's trying to run a kernel on any of the 2.6.21.* series in the meantime. (Isn't it a serious enough regression to fix in 2.6.21.*?) And he didn't suggest a workaround, except that alsa-firmware package which doesn't actually contain the firmware for that card. Looks like it's left to the user to make things work.

So here's what to do: it turns out that if you take a 2.6.21 kernel, and substitute the whole sound/pci/ymfpci directory from a 2.6.20 kernel source tree, it builds and boots just fine. And I'm off and running with a standalone apm kernel with no acpi; sound works, and I can finally build GIMP again.

So it's been quite a week of workarounds. You know, I used to argue with all those annoying "Linux is not ready for the desktop" people. But sometimes I feel like Linux usability is moving in the wrong direction. I try to imagine explaining to my mac-using friends why they should have to edit /etc/X11/xorg.conf because their distro set up a configuration that makes Firefox crash, or why they need to build a new kernel because the distributed ones all crash or hang ... I love Linux and don't regret using it, but I seem to need workarounds like this more often now than I did a few years ago. Sometimes it really does seem like the open source world is moving backward, not forward.

Tags: linux, ubuntu, mozilla, firefox, kernel, audio
[ 22:24 Jun 28, 2007    More linux | permalink to this entry ]

A Kitfox Extension

For a bit over a year I've been running a patched version of Firefox, which I call Kitfox, as my main browser. I patch it because there are a few really important features that the old Mozilla suite had which Firefox removed; for a long time this kept me from using Firefox (and I'm not the only one who feels that way), but when the Mozilla Foundation stopped supporting the suite and made Firefox the only supported option, I knew my only choice was to make Firefox do what I needed. The patches were pretty simple, but they meant that I've been building my own Firefox all this time.

Since all my changes were in JavaScript code, not C++, I knew this was probably all achievable with a Firefox extension. But never around to it; building the Mozilla source isn't that big a deal to me. I did it as part of my job for quite a few years, and my desktop machine is fast enough that it doesn't take that long to update and rebuild, then copy the result to my laptop.

But when I installed the latest Debian, "Etch", on the laptop, things got more complicated. It turns out Etch is about a year behind in its libraries. Programs built on any other system won't run on Etch. So I'd either have to build Mozilla on my laptop (a daunting prospect, with builds probably in the 4-hour range) or keep another system around for the purpose of building software for Etch. Not worth it. It was time to learn to build an extension.

There are an amazing number of good tutorials on the web for writing Firefox extensions (I won't even bother to link to any; just google firefox extension and make your own choices). They're all organized as step by step examples with sample code. That's great (my favorite type of tutorial) but it left my real question unanswered: what can you do in an extension? The tutorial examples all do simple things like add a new menu or toolbar button. None of them override existing Javascript, as I needed to do.

Canonical URL to the rescue. It's an extension that overrides one of the very behaviors I wanted to override: that of adding "www." to the beginning and ".com" or ".org" to the end of whatever's in the URLbar when you ctrl-click. (The Mozilla suite behaved much more usefully: ctrl-click opened the URL in a new tab, just like ctrl-clicking on a link. You never need to add www. and .com or .org explicitly because the URL loading code will do that for you if the initial name doesn't resolve by itself.) Canonical URL showed me that all you need to do is make an overlay containing your new version of the JavaScript method you want to override. Easy!

So now I have a tiny Kitfox extension that I can use on the laptop or anywhere else. Whee!

Since extensions are kind of a pain to unpack, I also made a source tarball which includes a simple Makefile: kitfox-0.1.tar.gz.

Tags: tech, web, mozilla, firefox, software
[ 10:59 May 27, 2007    More tech/web | permalink to this entry ]

The Pesky "Unresponsive Script" Dialog

For quite some time, I've been seeing all too frequently the dialog in Firefox which says:

A script on this page may be busy, or it may have stopped responding. You can stop the script now, or continue to see if the script will complete.
[Continue] [Stop script]

Googling found lots of pages offering advice on how to increase the timeout for scripts from the default of 5 seconds to 20 or more (change the preference dom.max_script_run_time in about:config. But that seemed wrong. I was seeing the dialog on lots of pages where other people didn't see it, even on my desktop machine, which, while it isn't the absolute latest and greatest in supercomputing, still is plenty fast for basic web tasks.

The kicker came when I found the latest page that triggers this dialog: Firefox' own cache viewer. Go to about:cache and click on "List Cache Entries" under Disk cache device. After six or seven seconds I got an Unresponsive script dialog every time. So obviously this wasn't a problem with the web sites I was visiting.

Someone on #mozillazine pointed me to Mozillazine's page discussing this dialog, but it's not very useful. For instance, it includes advice like

To determine what script is running too long, open the Error Console and tell it to stop the script. The Error Console should identify the script causing the problem.

Error console? What's that? I have a JavaScript Console, but it doesn't offer any way to stop scripts. No one on #mozillazine seemed to have any idea where I might find this elusive Error console either. Later Update: turns out this is new with Firefox 2.0. I've edited the Mozillazine page to say so. Funny that no one on IRC knew about it.

But there's a long and interesting MozillaZine discussion of the problem in which it's clear that it's often caused by extensions (which the Mozillazine page had also suggested). I checked the suggested list of Problematic extensions, but I didn't see anything that looked likely.

So I backed up my Firefox profile and set to work, disabling my extensions one at a time. First was Adblock, since it appeared in the Problematic list, but removing it didn't help: I still got the Unresponsive script when viewing my cache.

The next try was Media Player Connectivity. Bingo! No more Unresponsive dialog. That was easy.

Media Player Connectivity never worked right for me anyway. It's supposed to help with pages that offer videos not as a simple video link, like movie.mpeg or movie.mov or whatever, but as an embedded object in the page which insists on a specific browser plug-in (like Apples's QuickTime or Microsoft's Windows Media Player).

Playing these videos in Firefox is a huge pain in the keister -- you have to View Source and crawl through the HTML trying to find the URL for the actual video. Media Player Connectivity is supposed to help by doing the crawl for you and presenting you with video links for any embedded video it finds. But it typically doesn't find anything, and its user interface is so inconsistent and complicated that it's hard to figure out what it's telling you. It also can't follow the playlists and .SMIL files that so many sites use now. So I end up having to crawl through HTML source anyway.

Too bad! Maybe some day someone will find a way to make it easier to view video on Linux Firefox. But at least I seem to have gotten rid of those Unresponsive Script errors. That should make for nicer browsing!

Tags: tech, web, mozilla, firefox
[ 12:07 May 05, 2007    More tech/web | permalink to this entry ]

Disabling mailto links

Every time I click on a mailto link, Firefox wants to bring up Evolution. That's a fairly reasonable behavior (I'm sure Evolution is configured as the default mailer somewhere on my system even though I've never used it) but it's not what I want, since I have mutt running through a remote connection to another machine and that's where I'd want to send mail. Dismissing the dialog is an annoyance that I keep meaning to find a way around.

But I just learned about two excellent solutions:

First: network.protocol-handler.warn-external.mailto
Set this preference to TRUE (either by going to about:config and searching for mailto, then doubleclicking on the line for this preference, or by editing the config.js or user.js file in your firefox profile) and the next time you click on a mailto link, you'll get a confirmation dialog asking whether you really want to launch an external mailer.

"Ew! Cancelling a dialog every time is nearly as bad as cancelling the Evolution launch!" Never fear: this dialog has a "Don't show me this again" checkbox, so check it and click Cancel and Firefox will remember. From then on, clicks on mailto links will be treated as no-ops.

"But wait! It's going to be confusing having links that do nothing when clicked on. I'm not going to know why that happened!" Happily, there's a solution to that, too: you can set up a custom user style (in your chrome/userContent.css directory) to show a custom icon when you mouse over any mailto link. Shiny!

Tags: tech, web, firefox, mozilla
[ 20:19 Aug 04, 2006    More tech/web | permalink to this entry ]

Firefox for Presentations: Hiding the URLbar

I've long been an advocate of making presentations in HTML rather than using more complex presentation software such as PowerPoint, Open Office Presenter, etc. For one thing, those presentation apps are rather heavyweight for my poor slow laptop. For another, you can put an HTML presentation on the web and everyone can see it right away, without needing to download the whole presentation and fire up extra software to see it.

The problem is that Mozilla's fullscreen mode doesn't give you an easy way to get rid of the URL/navigation bar, so your presentations look like you're showing web pages in a browser. That's fine for some audiences, but in some cases it looks a bit unpolished.

In the old Mozilla suite, I solved the problem by having a separate profile which I used only for presentations, in which I customized my browser to show no urlbar. But having separate profiles means you always have to specify one when you start up, and you can't quickly switch into presentation mode from a running browser. Surely there was a better way.

After some fruitless poking in the source, I decided to ask around on IRC, and Derek Pomery (nemo) came up with a wonderful CSS hack to do it. Just add one line to your chrome/userChrome.css file.

In Firefox:

#toolbar-menubar[moz-collapsed=true] + #nav-bar { display: none !important; }

In Seamonkey:

#main-menubar[moz-collapsed=true] + #nav-bar { display: none !important; }

This uses a nice CSS trick I hadn't seen before, adjacent sibling selectors, to set the visibility of one item based on the state of a sibling which appears earlier in the DOM tree.

(A tip for using the DOM Inspector to find out the names of items in fullscreen mode: since the menus are no longer visible, use Ctrl-Shift-I to bring up the DOM Inspector window. Then File->Inspect a Window and select the main content window, which gets you the chrome of the window, not just the content. Then you can explore the XUL hierarchy.)

This one-line CSS hack turns either Firefox or Seamonkey into an excellent presentation tool. If you haven't tried using HTML for presentations, I encourage you to try it. You may find that it has a lot of advantages over dedicated presentation software.

Addendum: I probably should have mentioned that View->Toolbars->Navigation Controls turns off the toolbar if you just need it for a one-time presentation or can't modify userChrome.css. You have to do it before you flip to fullscreen, of course, since the menus won't be there afterward, and then again when you flip back. I wasn't happy with this solution myself because of the two extra steps required every time, particularly because the steps are awkward since they require using the laptop's trackpad.

Tags: tech, web, firefox, speaking
[ 16:59 Apr 25, 2006    More tech/web | permalink to this entry ]

How to Search Your Mozilla Cache

Ever want to look for something in your browser cache, but when you go there, it's just a mass of oddly named files and you can't figure out how to find anything?

(Sure, for whole pages you can use the History window, but what if you just want to find an image you saw this morning that isn't there any more?)

Here's a handy trick.

First, change directory to your cache directory (e.g. $HOME/.mozilla/firefox/blahblah/Cache).

Next, list the files of the type you're looking for, in the order in which they were last modified, and save that list to a file. Like this:

% file `ls -1t` | grep JPEG | sed 's/: .*//' > /tmp/foo

In English: ls -t lists in order of modification date, and -1 ensures that the files will be listed one per line. Pass that through grep for the right pattern (do a file * to see what sorts of patterns get spit out), then pass that through sed to get rid of everything but the filename. Save the result to a temporary file.

The temp file now contains the list of cache files of the type you want, ordered with the most recent first. You can now search through them to find what you want. For example, I viewed them with Pho:

pho `cat /tmp/foo`

For images, use whatever image viewer you normally use; if you're looking for text, you can use grep or whatever search you lke. Alternately, you could ls -lt `cat foo` to see what was modified when and cut down your search a bit further, or any other additional paring you need.

Of course, you don't have to use the temp file at all. I could have said simply:

pho `ls -1t` | grep JPEG | sed 's/: .*//'`

Making the temp file is merely for your convenience if you think you might need to do several types of searches before you find what you're looking for.

Tags: tech, web, mozilla, firefox, pipelines
[ 21:40 Oct 10, 2005    More tech/web | permalink to this entry ]

Hacking Mozilla Extension Versions

Mozilla Firefox's model has always been to dumb down the basic app to keep it simple, and require everything else to be implemented as separately-installed extensions.

There's a lot to be said for this model, but aside from security (the need to download extensions of questionable parentage from unfamiliar sites) there's another significant down side: every time you upgrade your browser, all your extensions become disabled, and it may be months before they're updated to support the new Firefox version (if indeed they're ever updated).

When you need extensions for basic functionality, like controlling cookies, or basic sanity, like blocking flash, the intervening months of partial functionality can be painful, especially when there's no reason for it (the plug-in API usually hasn't changed, merely the version string).

It turns out it's very easy to tweak your installed plug-ins to run under your current Firefox version.

1. Locate your profile directory (e.g. $HOME/firefox/blah.blah for Firefox on Linux).
2. Edit profiledirectory/extensions/*/install.rdf
3. Search for maxVersion.
4. Update it to your current version (as shown in the Tools->Extensions dialog).
5. Restart the browser.

Disclaimer: Obviously, if the Firefox API really has changed in a way that makes it incompatible with your installed extensions, this won't be enough. Your extensions may fail to work, crash your browser, delete all your files, or cause a massive meteorite to strike the earth causing global extinction. Consider this a temporary solution; do check periodically to see if there's a real extension update available.

More information on extension versioning (may be out of date).

Tags: tech, web, mozilla, firefox
[ 18:47 Oct 04, 2005    More tech/web | permalink to this entry ]

Catching Up on Firefox Regressions

I spent a little time this afternoon chasing down a couple of recent Firefox regressions that have been annoying me.

First, the business where, if you type a url into the urlbar and hit alt-Enter (ctrl-Enter in my Kitfox variant) to open a new tab, if you go back to the old tab you still see the new url in the urlbar, which doesn't match the page being displayed there.

That turns out to be bug 227826, which was fixed a week and a half ago. Hooray!

Reading that bug yielded a nice Mozilla tip I hadn't previously known: hitting ESC when focus is in the urlbar will revert the urlbar to what it should be, without needing to Reload.

The other annoyance I wanted to chase down is the new failure of firefox -remote to handle URLs with commas in them (as so many news stories have these days); quoting the url is no help, because it no longer handles quotes either. That means that trying to call a browser from another program such as an IRC client is doomed to fail for any complex url.

That turns out to be a side effect of the check-in for bug 280725, which had something to do with handling non-ASCII URLs on Windows. I've filed bug 298960 to cover the regression.

That leaves only one (much more minor) annoyance: the way the selection color has changed, and quite often seems to give me white text on a dingy mustard yellow background. I think that's because of bug 56314, which apparently makes it choose a background color that's the reverse of the page's background, but which then doesn't seem to choose a contrasting foreground color.

It turns out you can override this if you don't mind specifying a single fixed set of selection colors (instead of having them change with the colors of every page). In userChrome.css (for the urlbar) and userContent.css (for page content):

::-moz-selection {
  background-color: magenta;
  color: white;
}

(obviously, pick any pair of colors which strikes your fancy).

Tags: tech, web, mozilla, firefox
[ 20:45 Jun 27, 2005    More tech/web | permalink to this entry ]

Mozilla tip: highlight links that would open a new window

Investigating some of the disappointing recent regressions in Mozilla (in particular in handling links that would open new windows, bug 278429), I stumbled upon this useful little tidbit from manko, in the old bug 78037:

You can use CSS to make your browser give different highlighting for links that would open in a different window.

Put something like this in your [moz_profile_dir]/chrome/userContent.css:

a[target="_blank"] {
  -moz-outline: 1px dashed invert !important;
  /* links to open in new window */
}

a:hover[target="_blank"] {
  cursor: crosshair; text-decoration: blink;
  color: red; background-color: yellow
  !important
}

a[href^="http://"] {
  -moz-outline: 1px dashed #FFCC00 !important;
  /* links outside from current site */
}

a[href^="http://"][target="_blank"] {
  -moz-outline: 1px dashed #FF0000 !important;
  /* combination */
}

I questioned the use of outlines rather than colors, but then realized why manko uses outlines instead: it's better to preserve the existing colors used by each page, so that link colors go along with the page's background color.

I tried adding a text-decoration: blink; to the a:hover style, but it didn't work. I don't know whether mozilla ignores blink, or if it's being overridden by the line I already had in userContent.css,

blink { text-decoration: none ! important; }

though I doubt that, since that should apply to the blink tag, not blink styles on other tags. In any case, the crosshair cursor should make new-window links sufficiently obvious, and I expect the blinking (even only on hover) would have gotten on my nerves before long.

Incidentally, for any web designers reading this (and who isn't, these days?), links that try to open new browser windows are a longstanding item on usability guru Jakob Neilsen's Top Ten Mistakes in Web Design, and he has a good explanation why. I'm clearly not the only one who hates them.

For a few other mozilla hacks, see my current userChrome.css and userContent.css.

Tags: tech, web, mozilla, firefox
[ 13:03 Jan 17, 2005    More tech/web | permalink to this entry ]