DOM issues in IE - javascript

I've developed an application that I had tested in Chrome and Firefox but then upon testing in IE I noticed a few things weren't working quite as they should so I made a couple tweaks and everything seemed to be working as it should.
However, as if by some sort of magic when I was going through another round of testing in IE I started noticing that I was getting a lot of debugging errors that I had previously been getting.
They all seem to be to be DOM related with IE being unable to get the value of properties because the object is either null or undefined.
I was having none of these issues previously and I have absolutely no idea what might have changed to be causing this but does anyone have any experience of this sort of issue and have some suggestions as to how to resolve the issue?
I've had a look through all the different pages and functions I've been working on the last couple hours but can see nothing obvious that might be causing this.
Any help would be very much appreciated.
Thanks!

The latest versions of IE come with a pretty decent script debugger. If you press F12, a developer tools window will pop up. Click on the "Script" tab and start working your problem from there. Its not as robust or efficient as firebug or chrome's developer console, but its better than nothing and more often than not can get you pointed in the right direction when it comes to squishing IE bugs.

Related

Javascript is acting buggy on Chrome

It's a little hard to describe as I have very little knowledge about Javascript, but it seems to be causing some issues with my Chrome browser. The best way I can say it is that a lot of things that use Javascript are broken. For example, when I visit a Wikipedia page and try to click 'show' on a nav-box, it takes me to the top of the page instead of opening the box. These things still work on IE, so I know this issue at least limited to Chrome. I don't know how this issue started. What exactly is going on here, and how can I fix it?
It's been resolved. I did a full reinstallation of Chrome.

Chrome "Unresponsive Page" false-positive (since Chrome 32)

Ever since Chrome updated itself to version 32, I have been experiencing aggravating bugs. One of the worst is when editing the DOM using the Web Inspector, and Chrome will about every minute start popping up this dialog, which yanks focus from the Web Inspector:
It's complaining about the Web Inspector itself being "unresponsive", when it really isn't, and nothing's gone wrong.
This particular page I'm messing with is making use of the mutation-summary library. Perhaps the bug in Chrome that thinks stuff is unresponsive could be related to setting various continuously-running setTimeouts. I say this because I observe similar behavior in the web app we build at work where this has also started happening (and is equally annoying).
The workaround is I believe it is possible to just ignore the dialog and work can continue. I wonder if anyone else (or everyone else) has been experiencing this issue?
I started getting this problem as well.
In searching, I came accross this issue https://code.google.com/p/chromium/issues/detail?id=335248.
As best I figured out, the bug is related to:
Windows 7/8 with Aero Theme
Scrollbars on pages (such as in the developer console)
Pages with popups (in particular Window.open() calls)
I guess they are slated to push the fix into version 33...and maybe leave the stable* 32 how it is (although I hope not).
So there are a few options:
Switch away from Aero Theme until version 33 is in stable
Upgrade to the beta channel, i.e. version 33
Click on the Wait button every 30 seconds whenever the chrome developer tools is open.
Update:
Chrome has released a hotfix into the version 32 stable channel. http://googlechromereleases.blogspot.ro/2014/01/stable-channel-update_27.html
Thanks to #probackpacker for bringing it to my attention.
I have experienced this as well on Windows, it seems that this will happen in general when using the browser (not only within the web inspector). It also seems to happen more often when loading flash content (such as a game). The browser and flash areas are responding normally, but the browser thinks that they are not for whatever reason. Pressing wait seems to hide the dialog for a few minutes until it will re-appear again.
I've read that this bug is fixed in the next beta (version 33).
Regards,
Moses
I have also experienced this issue. The change of theme workaround has worked, and the Chromium team has provided the following update today:
... We understand your frustration and are actively working to resolve
it. When you add that comment, it’s confusing the comments around
whether we’re able to fully fix it on canary. If we can confirm it’s
fully fixed in canary, we can merge into the stable channel and
everyone can get the fix. So please refrain from saying thatyou’re
having this problem, too. I assure you we’re actively working on a
fix.
This statement was taken from Chromium ticket #335248.
Okay here’s the solution you can do without changing your theme, right click on my computer, go to your System Properties, and then go to "Advanced", click on "Settings" under Performance, then check the below radio button. This seems to stop it
If the aero fix isn't working for you, download Chrome Beta
I have had this same issue with Chrome 32 (there are so many problems in the dev tools...) but it ONLY happens for me when I have the dev tools detached / undocked from the main browser window.
You might be able to avoid it by re-docking the devtools if you are using them in un-docked mode.
August 6, 2014 - I solved this by installing the latest Chrome Beta https://www.google.com/chrome/browser/beta.html
You can solve this problem in Chrome by following simple steps-
1-Go to Setting
2-Go to Advance Setting
3-Uncheck the "Use Hardware Acceleration when available".
I fixed that problem by linking modem directly to my PC, didn't reinstall or change Chrome or anything. I skipped connection through my wireless router which I think was the problem from the start... now all the pages Chrome couldn't load are loading with no problem at all. Maybe it's time to by a new router...

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 :)

Javascript tabifier not working in Chrome, but works fine on Firefox

I have little knowledge of javascript so I hope someone here could help me. The problem occurs on http://www.bestfreeandroidapps.com/ if you look on the right side there are 3 tabs with Categories, Comments and Recent Posts. When you click on them from Chrome, nothing happens (no errors in the console, just nothing), however it works fine in Firefox.
This theme uses a script calle Javascript tabifier from http://www.barelyfitz.com/projects/tabber/, however I even replaced the script on the theme with what was included in the original project and still doesn't work on Chrome. Does anyone have an idea of what might be wrong and why is this happening?
Thank you very much!
It works. I think its being cached by the browser, I've had similar problems lately. Restart browser/computer!

Tools to diagnose browser differences and problems

What are some tool to help uncover why for instance FF is rendering a page differently than chrome ie and safari. My issue is simply the images along the left side of my main body get stretched to the length of the page only in FF every other browser renders in perfectly!
If anyone cares to see the difference
http://tinyurl.com/7vkcvn5
Works in everything but FF
I sometimes have luck running a page that is exhibiting quirks through a validator just to check that there isn't a typo or something triggering the problem. Try http://validator.w3c.org/. Your page has many validation errors in it, so that could explain the rendering quirks. (Some people argue, correctly in my opinion, that in some situations validation errors are OK. This doesn't strike me as one of those situations.)
Might not answer your specific alignment issue, but for differences in browser support, I usually go to http://quirksmode.org/ and http://caniuse.com/. To find polyfills to patch over browser differences, I usually go to http://html5please.com/.
browserstack.com
and
spoon.net/browsers
are two of the best tools I have been using.

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