Open Bug 1141277 Opened 9 years ago Updated 2 years ago

FF36+ freezes for ~2 minutes with open JS console (Firebug too) for sites with big JS


(Core :: General, defect)

36 Branch
Windows 7





(Reporter: marooned_mb, Unassigned)


User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0
Build ID: 20150122214805

Steps to reproduce:

FF 36 and 36.0.1 are freezing for aprox. 2 minutes when Firebug (with script tab enabled) or native JS console is enabled. I observe that on a page that I'm developing (closed beta but I can give access to a developer if needed). There is absolutely no issue with older FF (I downgraded to 35.0.1 to be able to work normally). I've tried several other random sites but could not find suitable one to confirm the issue. If you know any site with quite big JS, I can retest.
Our JS is aprox. 3,7MB, over 100k of lines (work in progress, no cleaning yet).

I've tested it on fresh install on virtual box to confirm it's not any of my extensions.

Actual results:

Firefox 36+ freezes for ~2 minutes with open JS console.

Expected results:

Firefox works as prior to 36 (35 is just fine).
I've also tested in Nightly build 39.0a1 (2015-03-09) (with multiprocess disabled to be able to enable Firebug) and it's also freezing but for a bit shorter time (like ~30s) - however, still much longer than FF35 that do not freeze at all during page load.

It can take longer in FF 87, but since it's easy to miss an open console if it's behind the pages, it can still cause trouble.

Severity: normal → S3
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