The Pesky "Unresponsive Script" Dialog (Shallow Thoughts)

Akkana's Musings on Open Source, Science, and Nature.

Sat, 05 May 2007

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!

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