Develop Reference

Chrome User Agent not displaying script - CSS fix?

I installed a WP theme recently and am having trouble getting a Facebook conversion box to display when I visit my site through Chrome. This problem doesn't exist on Firefox.
The response I get on Chrome is no visible pop-up box, but upon inspecting the element, I do see the code for the box in my header.php with a line from the Chrome User Agent saying:
script {
display: none;
Is there a CSS solution to override the User Agent and get the script to display? Again, I have no problems with the theme on Firefox. Here's a link to my site.
Thanks in advance!

I think I found the source of your problem. It's a browser extension.
Your conversion box appears on my personal laptop. However, it doesn't on my work laptop. That lead me to believe that it was a conflict with the script & a browser extension. So I opened your site in an incognito window. Voila! it worked. The next step was figuring out which extension was blocking it. For me, it is LastPass (my work requires the use of LastPass).
If you have LastPass enabled as an extension, disable it. Then test again.
It'd also be a good idea to get these console errors figured out:
Uncaught SyntaxError: Unexpected token ; (index):476
carouFredSel: No element found for "#foo1". jquery.carouFredSel-6.2.1.js?ver=3.8.3:4232
Uncaught ReferenceError: paginateVal is not defined cgview.js?ver=3.8.3:28
Solutions
Unfortunately, there isn't much you can do about people's individual extensions. If this is an absolutely critical feature for you, I'd look at finding a different implementation of it. One that does not conflict with common extensions (that's the easy option).
The other option (harder) is to look into the code of the plugin/script that you're using for the conversion box and identify the conflict.
Last option (hardest) is to look at LastPass extension source code and identify the bug that is preventing other scripts from running. I've had issues with LastPass interfering with javascript in the past.

Firebug says "No Javascript on this page", even though JavaScript does exist on the page

Why does Firebug say there is No Javascript on this page when there are clearly loads of JavaScript on the page. I even reloaded the page several time to make sure but it still show the same message.
It never used to do that before, but all of a sudden it misbehaves.
Is it because of some configuration issues or because of something else?

As of Firefox version 50, it seems that Firebug will no longer work as Mozilla are migrating to Firefox Devtools. The tab Tools/Web Developer has a 'debugger' option. See this page for a discussion on the migration. Read all the posts dated 19 November for further information.
It seems to me that the option gives less functionality but Firebug per se is never going to be fixed for Firefox 50 and beyond

EDIT 2017 April
This answer is now outdated and I'm not even testing it anymore because I'm no longer using Firebug (a shame, I loved it years ago in a time it was The tool of trade for web developing).
EDIT 2014 November
The original answer is now more than a year outdated due to firebug evolution.
Thanks to #AmadeusDrZaius to keep it on tracks
Answer for outdated firebug versions
For anyone still with this problem after updating Firebug.
Just click Clear Activation List option inside the Firebug menu.
For those who can't find it, note that "Clear Activation List" shows up in the dropdown from the Firebug icon in the toolbar, but not the Tools > Web Developer > Firebug menu.
I guess due to the bug previous hitting your working page it stays listed as "no activate FB for this site please".

I encountered No Javascript on this page after upgrading Firefox to ver 50.0, with Firebug ver 2.0.18. I tried refreshing Firefox, even completely uninstall Firefox and installed again. Nothing works for me.
A couple of hours later, I downgraded Firefox to 49.0.2, and voila, it works right away. I downloaded the old version here.

I tried everything on this list and nothing worked for me except resetting Firefox like so:
https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-problems

I realize there are already 10 answers to this question, but in my case none of them helped. I'm running Firefox version 39.0 and Firebug version 2.0.11. The only fix is to completely restart Firefox (i.e. not just the tab or instance with the problem).
Perhaps it's due to Firefox's over-usage of memory, or maybe there's a bug in Firebug. I can't speak to that, but what I do know is it didn't work. I killed Firefox, opened the exact same page again with no changes made and now it works. This has happened to me numerous times and a complete restart always fixes it, but that's the only thing that does.

Since Firefox 49.0 and Firebug 2.0.18 the Script panel is broken. This is due to some internal Firefox API changes. And because Firebug is officially discontinued, this unfortunately won't get fixed anymore.
There was also a bug in Firebug 2.0.11 (and below) in combination with Firefox 39.0 causing this problem. This bug is filed as issue 7918.
It happens when the Script panel is enabled and you close Firebug and reopen it.
You can see two related error messages logged to the Browser Console (can be opened via Ctrl+Shift+J or Firebug menu > Developer > Browser Console):
error occurred while processing 'attach: TypeError: docShell is null
Stack: getChildDocShells#resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webbrowser.js:53:7
...
and
onPacket threw an exception: Error: Server did not specify an actor, dropping packet: {"error":"unknownError","message":"error occurred while processing 'attach: TypeError: docShell is null\nStack: getChildDocShells#resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webbrowser.js:53:7
...
Solution:
The only solution until this bug is fixed is to restart Firefox completely.

Similar things have happened to me because I forgot to add the closing tag.
DON'T do this:
<script src="some.url" type="text/javascript">
or
<script src="some.url" type="text/javascript"/>
DO this instead:
<script src="some.url" type="text/javascript"></script>

The same problem just happened to me. I thought that it was a problem in my scripts, but I checked google.com and the problem persisted.
My problem was that I had updated my version of FF and kept the old version of FireBug. When I updated FireBug and everything was solved.

From firefox 49, the fire bug will be built in and it is called fire-bug next. So the fire bug add on won't work properly and no issues will be solved. So you can use firefox inspector. See here for details information

If the problem only shows up on a single page, check that your script folder is referenced from current folder (".") or that's reachable from the server root ("/").
<script src="./scripts/pagescripts.js" type="text/javascript"></script>
may not be the same as
<script src="/scripts/pagescripts.js" type="text/javascript"></script>

As mentioned, sometimes there's a Javascript syntax error that invalidates the whole script. But I have also had this, and simply opening up the page in a new tab or window and refreshing firebug (disable, enable) gets the javascript to show up again.

One time this caught me out was when I published one of my sites and I was checking it out. No Javascript was working, there were no errors in the console and firebug showed no scripts.
It turned out that in that instance, I'd forgotten to allow the site in NoScript - so there really were no scripts being loaded.
Not sure if that's the problem you're facing but it's worth being aware of.

I also got this error when attempting to use Ajax to a different server than the one serving up the page. JavaScript only allows Ajax access to the server that served up the page.

This problem is STILL happening (Aug 2015) with Firefox 39.0.3 and Firebug 2.0.11
For people saying the code is wrong or missing end tags etc. all I did to get all the javascript to reappear in tab was to shut down Firefox and restart it. I didn't change anything. Also that "Clear Activation List" option didn't work (no idea what that means)

I upvoted #Tom_Thomson's answer above, but I am wondering if simply removing and then reinstalling the Firebug add-on might not have accomplished the same thing without losing all the other stuff like bookmarks.

FWIW this problem is still happening in August 2016. I'm using Firebug 2.0.17 with Firefox Dev Edition 50.0a2.
As a workaround, I'm able to use the Developer Tools, though they are not as robust as Firebug (when it's working).

Well Firefox native Inspector is good... I know that you will miss some things, but in general we can survive with it. The good news is... less one addon, FF will be faster :)

JS assets in a subdomain wont load on ff & ie but chrome is all good

We are building a Saas product and have purchased a bootstrap dashboard, all the JS/CSS assets are loaded though a sobdomain via our CDN.
Works perfectly on chrome but on ie and ff the components do not load properly, on ff I get the following errors:
TypeError: can't access dead object
ReferenceError: event is not defined
A link to a non working example is below (We don't want to give access to our working dashboard for commercial reasons) You can see the error when click on the "dropdown" menu item. As far as I can tell, all the assets are loading correctly.
http://hunchbuzz.com/acme/index.html
Any help would be appreciated.

Well, take your bugs one by one. Did you turn on the JavaScript Debugger when you tested your page in IE? In the F12 developer tools, select Script and then Start Debugging.
First there were a couple of errors in jquery.sparkline.min.js which I ignored for the moment. Then I tried clicking your 'dropdown' link and got this error:
SCRIPT438: Object doesn't support property or method 'preventDefault'
custom.js, line 3 character 1193
The highlighted code is (reformatted for readability):
$('.dropmenu').click( function(){
event.preventDefault();
// ...
});
Do you see the problem? What is event? The code should be:
$('.dropmenu').click( function( event ){
event.preventDefault();
// ...
});
The fact that it worked in any browser at all is probably due to the global event variable that some browsers create for compatibility with very old code.
Now back to the sparkline problems. I see it hitting two errors in jquery.sparkline.min.js, but with the minimized code the problem isn't jumping out at me the way the other one did.
When you're debugging, it would help a lot to load the non-minified versions of jquery.sparkline.js, custom.js, jQuery, etc. Then you'll have readable code to look at in the debugger, which should make it easier to spot these problems.

Show Javascript functions in real-time

Is there any tool or addon which can be used for testing or identifying Javascript functions in real time (i.e. on click or some events )..
e.g. on a website, I want to know after clicking on a link, which all JS functions are being called/executed..I know sometimes it is stragightforward from the code, but in case it uses JS libraries like jQuery, the actual function call is made from otside..
How can I do that?
*I'll really appreciate if, alongwith the addon, you just write a short description as to where can I find the Javascript finction tracking in that **
Thank you.

Try Firebug. It's one of the most useful firefox addons. Grab it here:
http://getfirebug.com/

Dragonfly (Opera), or Firebug extension for Firefox, or any other good javascript debugger

See Visual Event. It is a bookmarklet that overlays element event handler information.
FireQuery is available as a firefox plugin which adds handler information inside of firebug.

Firebug includes a JavaScript profiler. Give it a try.
http://getfirebug.com/javascript

In Chrome, right click the page and choose Inspect element, go to the console, start javascripting! Choose the scripts tag to get debugger functionality.

TinyMCE not working with Chrome when I dynamically setContent

I have a site that I put:
<body onload="ajaxLoad()" >
I have a Javascript function that then inserts data from my database into the text editor by using the setContent Javascript method of the textarea. It seems fine in Firefox and IE but in Chrome sometimes nothing shows up. There is no error, just a blank editor.
In the body section I have:
<textarea id="elm1" name="elm1" rows="40" cols="60" style="width: 100%">
</textarea>
In the head section I have:
function ajaxLoad() {
var ed = tinyMCE.get('elm1');
ed.setProgressState(1); // Show progress
window.setTimeout(function() {
ed.setProgressState(0); // Hide progress
ed.setContent('<p style="text-align: center;"><strong><br /><span style="font-size: small;">General Manager's Corner</span></strong></p><p style="text-align: center;">August 2009</p><p>It’s been 15<sup>th</sup> and so have a Steak Night (Saturday, 15<sup>th</sup>) and a shore Dinner planned (Saturday, 22<sup>nd</sup>) this month. urday, September 5<sup>th</sup>. e a can’t missed evening, shas extended it one additional week. The last clinic will be the week of August 11<sup>th</sup>. </p><p> Alt (Tuesday through Thursday) </p><p> I wouClub.</p><p> </p><p> </p><p> </p><p> <strong></strong></p>');
}, 1);
}
I am not sure if its some of the formatting that Chrome is rejecting but it seems like if TinyMCE can parse it in one browser, it should be able to do it in any browser, so I am confused.
Any suggestions?

Background:
For various reasons onload() is not considered the proper approach for loading Javascript, see for example Launching Code on Document Ready, with the most important/noticeable one being that Javascript code isn't run until the page has finished downloading entirely, including images and the like, which might take an eternity therefore (e.g. if an external banner ad server is down etc.).
Instead it is recommended to load Javascript as soon as the DOM is ready, but unfortunately there is no cross browser compatible native solution for this, see Getting notified when the page DOM has loaded (but before window.onload); please note that my entire answer is based upon the most excellent Javascript library jQuery, which offers a cross browser solution for this problem, consequently I'd definitely favor the two higher voted answers over the accepted solution myself.
Likely cause:
Your issue seems to be caused by the opposite behavior though: Chrome facilitates the WebKit rendering engine, just like Safari, and for the latter onload() is discussed to behave differently, see section When does onload fire? in Is Safari faster?. Another description of this problem specific to Chrome can be found in window.onload not working correctly in Chrome, without an explanation though.
In conclusion I suspect onload() to fire before the DOM is actually loaded completely, at least concerning the requirements of TinyMCE, which is notoriously fragile regarding issues like this and simply ceases to load.
Possible solution:
Just facilitating attribute defer on the script tag as outlined in window.onload not working correctly in Chrome is again not cross browser compatible, hence I'd simply go with the widely deployed and proven approach of using the already mentioned jQuery cross browser solution for the onload() problem, which is good practice anyway and should in principle take care of your inverse issue as well.
Update:
There are indeed some bugs filed against WebKit which could back my conclusion (no matter whether this behavior actually constitutes a bug or is intentional), see:
onload sometimes fired before all resources are loaded
window.onload fires before all subresources loaded
Window.onload is firing before image resources are loaded

I had a similar problem (editor not showing in chrome) and read in some forum, that if tinyMCE is unable to locate some files, it just stops loading. Try tracking down if everything is found using firebug's net tab (clear your cache first).

First of all; see to it that you have the latest version of TinyMCE.
I could not reproduce your problem given the information you provides. It seems just fine ( with the faked ajaxload ).
You could always try to go the "back entrance" in;
var myed = document.getElementById('elm1_ifr');
myed.contentDocument.getElementById('tinymce').innerHTML="<p style=\"text-align: center;\"><strong>hacking <span style=\"font-size: small;\">my</span> way in.</strong></p>";
Hope you good luck!

SOLUTION:
Ive been struggling with the TinyMCE toolbar not appearing in all kinds of secnarios....it would work in one user's IE browser, but not another. It would not work in Firefox or Chrome, etc.
Turns out if in the newest 3.3 version there are STILL bugs they have not fixed. This one occurs when in your webpage JavaScript code, where you instantiate the TinyMCE, if you added code for the plugin part where you load up two specific plugins, the toolbar fails to appear and you see HTML:
plugins:
"safari,spellchecker,pagebreak,style,layer,table,save,advhr,advimage,advlink,emotions,iespell,
inlinepopups,insertdatetime,preview,media,searchreplace,print,contextmenu,paste,directionality,
fullscreen,noneditable,visualchars,nonbreaking,xhtmlxtras,template,**imagemanager,filemanager**",
Remove all references to imagemanager and filemanager in your web page, then refresh your browser...
When you do, retest in Chrome and Firefox and IE and the TinyMCE suddenly appears! Wow....a miracle, huh?
Turns out their "main developer" hasn't fixed the issue but does explain it as such, if you want to try and still use those plugins and yet fix the problem. His quote is as follows:
"If the ImageManager/FileManager are old they might not use the new
scriptloader api. And the new 3.3 version will load all dependent
scripts async instead of sync. - Spocke - Main developer of TinyMCE"

There are a few ways to set content in a TinyMCE editor. If you want the content to be there when the page first loads, you can just put it between the tags.
Otherwise, you can do this through script in the following way:
window.onload = function() {
tinyMCE.getInstanceById("ProfileText").setContent('test');
};
I have wrapped the code in a window.onload block. If you have other functions that set content dynamically through this way after the TinyMCE editor has already loaded, then you do not need that.

There is an option oninit for the function tinyMCE.init(), put your method there:
tinyMCE.init({
oninit: function(){
tinyMCE.activeEditor.setContent('blah');
}
});
It works this way.
The editor is not fully loaded on document load event, as it the editor loader will post-load a bunch of files.

same problem here, ie needs
var ed = tinyMCE.get('content');
ed.setContent('zzz');
other browsers
document.getElementById("content").innerHTML="zzz";
i am quite disapointed
will need to check browser in javascript to get it working properly, thats suxx