JS that creates lots of events (in the case below an ever increasing set of events) can almost completely freeze the UI - so much so that you can't even close the tab. The runaway script dialog never comes up - killing the browser is pretty much the only path. Some sort of runaway detection would be desirable. 2 examples: function f() { for (var i = 0; i < 32; ++i) setTimeout(f); } setTimeout(f); and (derived from a real bug): function chatRoomClass(){}; var reconnection; var ctr = 32; iv=function () { cr.ws.close(); for(j=0;j<ctr;j++) cr.initws(); } chatRoomClass.prototype.initws=function() { self=this; if("WebSocket"in window) { if(this.ws!=null) { this.ws.close(); } this.ws=new WebSocket("ws://doesntreallyexist.tv:88/1"); var self=this; reconnection=setInterval(function(){;clearInterval(reconnection); iv();}, 1); } }; cr = new chatRoomClass(); cr.initws();

I believe this should be fixed now that bug 1300659 has landed.