Website breaks when Firebug is enabled - javascript

I use Firebug to do most of my web debugging. In one of the web applications I'm working on, the application breaks when Firebug is enabled; it seems that some JS resources (mainly jQuery) aren't being loaded. When I disable Firebug, the site works great. Any ideas on how Firebug might be interfering with how the site runs, and what can be done to fix it?

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IE11 javascript fails unless debugger is launched

I hava situation where some javascript a web page works fine in Safari and Chrome, but fails in IE11. Unfortunately due to issues with confidentiality I cannot put the javascript up here.
In IE11 the web page's java script fails to operate correctly. By that I mean some of the javascript works and some doesn't. With no errors displayed or any other indication of whats wrong.
If I try to debug the page using IE's developers tools, all the javascript works perfectly without any errors or issues.
Searching on the net I found many people with the same IE problem - fails normally, works when debugging. The main issues they talk about is the console.log(...) statement. I checked my javascript and don't have any console.log(...) statements.
I then saw a stackoverflow thread where adding a cache:false to the $.ajax({... calls solved the issue. I added the same flag but the problem still persists.
Are there any other bugs I've not found?
The web page is using jQuery to handle most of it's manipulation of the DOM with a single $.ajax... call and a series of $.get(... calls polling the server.
How to debug your web pages.....IE11 tips.
All modern web browsers suppress scripting error messages and warnings by default. (In the early days web browsers would halt page loading/rendering and display a script error message with an alert statement)... this gives the best user experience who isn't concerned with the internal workings of web site code.
So, scripting errors will only BREAK execution if:
1. The browser debug tool is opened. and
2. The developer tools' Debug tab setting for Break on Exceptions has been turned on.
So to debug your web pages.
1. navigate to about:blank to start a testing cycle.....press f11 to display the dev tool, select "Break on all exceptions" from the dropdown (looks like a stop sign). Pin the dev tool to the bottom of the browser.
2. Return to the browser address bar and navigate to your test site (typed address of paste and go)...
The dev tool will now break on ALL exceptions and you will list them in the console tab.
IE has built-in content blocking and has ActiveX filtering (ad blocking) which can affect outcomes. You need to configure Internet Options so that the IE dev tool console will record any blocked content or security (XSS) errors.
Tools>Internet Options>Advanced tab, check "Always record developer console messages".
Also on the Emulation tab of the IE dev tool you will find the Emulation Mode (aka documentMode) that IE is using, and how it was established eg. x-ua meta, Enterprise site mode list, user Compatibility View list, etc
If you are developing an internal company website, the emulation mode used by IE may be for an earlier version of IE.. (IE8 on XP).. you should include this information with your questions.
You should also include the IE security zone that your site has been mapped to.. File>Properties menu in IE.... eg. Intranet zone as this can have different security and blocked content outcomes.
finally, the first step in troubleshooting web browser issues is to test in noAddons mode (for IE, winkey+r>iexplore.exe -extoff ). IE has built-in form-fillers and popup blockers... third-party addons can affect the outcomes expected.

Why can't I run any of my JavaScript in Google Chrome?

Can't remove JavaScript errors or run any of my own JavaScript on my page. Getting "function undefined" errors. Console showing Javascript errors coming from trendtext.eu. Is this malware?
Responsive Web Design Tester silently loads javascript activity tracking library from trendtext.eu website which collects information about what you do, what pages you visit and how knows what else.
It is the same spyware script that was reported here http://news.softpedia.com/news/download-manager-s3-firefox-add-on-spies-on-users-495228.shtml
It is likely the Chrome extension "Responsive Web Design Tester" crashing javascript on your web pages. Extension must've been compromised and appears to be removed from the Chrome Extension web store now. To remove it, open Chrome and select the top left menu option "Chrome". Click "Preferences" and select "Extensions". Scroll down to "Responsive Web Design Tester" and uncheck the "Enable" option. Feel free to delete the plugin as well, as it appears to be unsupported at this time.

Web page seems not to be loaded on old Android browsers, how to debug this issue?

I build a demo website (sources) which uses socket.io connections and Ractive.js, and works just fine.
On desktop, there is nothing seems suspicious, but on the mobile browser, it seems to be loading forever. While it is loading, I can fully use the page. Only effect is, since page is using Javascript codes a lot, page responses is slowing down. When I click the "stop" button on the browser, it immediately stops loading "the rest" of web page and I can use entire page as intended, even faster (than it was loading).
I tried to debug with firebug, but I found nothing, because it works flawlessly on desktop browser.
I would download the ADB plugin for Chrome, then i would look at performance profiling. https://developer.chrome.com/devtools/docs/cpu-profiling

Why does Firefox suddenly disable Javascript by itself?

I am using Firefox 28.0 on Mac OS 10.6.8. Sometimes during web development, probably after my application crashes, Firefox suddenly disables Javascript in one particular tab. So my application would be all weird and not work until I restart Firefox. The script panel would say that the page has no scripts, and if I open another page with Javascript in the same tab, it would not work either.
Is it some kind of safety feature? Is it documented anywhere? Note that I also have Firebug installed, and I managed to crash Firefox by profiling my app in Firebug on more than one occasion.
I checked about.config; javascript.enabled is set to true.

My FanGate code on my works outside of FB, but not when viewed within the FB Fan Page

I am very new to FB programming and JavaScript as well (a long time ASP.NET programmer). I am trying to use the JavaScript SDK to create a fangate. The page works perfectly when I run my page directly (http://wmssupportforum.com/FacebookPages/FacebookWMSJobs.aspx), but when it is pulled up from within my Fan Page (http://www.facebook.com/pages/WMS-Support-Forum/207356652683205?sk=app_143965989047095), it doesn't work, i.e. it doesn't Show my Liked div and hide my UnLiked div, etc.
I have no idea how to debug this from within FB...(when I render it in IE directly from my site, I can debug it, but when I try to debug the Fan Page version, IE's dev tools won't load the script to debug it...it just hangs).
Any help is greatly appreciated!!!
Thanks in advance,
Chad
UPDATE: It looks like the difference is only an issue in IE v9. I don't have the same issues in Firefox or Chrome. So in IE9, pulling my page up on one IE Browser tab directly at the page URL works, but when pulled up through my FB FanPage on another IE tab, it doesn't work...seems like it is hanging as the HTML tab in IE Developer Tools window just says Loading....
It's a webserver issue. Believe it or not, but by adding in a simple P3P header to your response will solve the IE issue. See: Cookie blocked/not saved in IFRAME in Internet Explorer and also http://www.hanselman.com/blog/TheImportanceOfP3PAndACompactPrivacyPolicy.aspx

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