I am getting a message sometimes in Firefox, which says that a script is frozen or damaged. The script which the dialog mentions is:
http://example.com/:1
I can not reproduce the dialog at the moment, but the :1 looks suspicious. What could that mean?
The message in Firefox is similiar to this one: A script on this page may be busy, or It may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.
Thanks!
If a JavaScript error has a colon followed by a number, the number is what line in the script that caused the error.
For example, foo-bar.js:57 means the error occurred on the 57th line in "foo-bar.js".
The reason why your error says http://example.com/ is because the server of "example.com" is configured to display the home-page without saying "/home.html" in the URL, so you don't see anything after the "/". The JavaScript of "example.com" is probably inline, so it doesn't say http://example.com/script.js:1 either.
* I used fake examples for the "example.com" thing.
Related
The error in the title is caught by Sentry (an error tracking tool). Below is a screenshot from Sentry - showing the stack trace.
Note: the script /en_US/iab.autofill.payment.js where handleMessage is located is loaded from Facebook (link here), and I couldn't find this script in the javascript bundle, nor anything related to it. I assume it's loaded by a 3rd party script - I'm using Google Tag Manager (which is also loading Facebook Pixel), Segment (loading Hotjar and Mixpanel), and Snapchat. The error started to appear without any changes in these scripts or the services that they're sending data to.
Note 2: It seems that the error is triggered quite often, about 10-15% of the time. I tried to reproduce it but given that it's a handled error, it doesn't show in the dev console.
Any direction on where to look would be much appreciated.
I'm seeing this a lot, and it seems to be coming 100% from users using Facebook browser on iOS (I guess this is the browser you see when you're using the Facebook app).
I tried to debug this with a snippet:
<script>
window.addEventListener('message', function (e) {
console.log(e);
JSON.parse(e.data);
console.log('foo');
}, false);
</script>
This is from the library you linked. Assuming that e.data is JSON string (not e.g. an object?), without any safeguard seems to be breaking things.
The second console.log doesn't fire, so I think this is causing some unexpected behaviours in my case (buttons not reacting to clicks with js listeners etc)
I don't know if there is a workaround or a way to protect from this in Facebook embedded browser (I guess it's loaded there)
Looking forward to hear more info
i have meet that too, its because the one script facebook inject in. will postMessage(Object), but the another script will listen the message and try to JSON.parse an object ,so it will came out a error. u can use 'vconsole' lib, and add a window.addEventListener('message',(e)=>{console.log(e.data)}) and u can see that
Apparently, the issue went away after a couple of weeks without changing anything on my side.
I know that to debug content script use normal web developer tools (https://developer.mozilla.org/en/docs/Mozilla/Add-ons/WebExtensions/Debugging#Debugging_content_scripts), and this works perfect. debugger keyword works as intended.
But in this exact situation things get broken:
addon.id = "123-568-485"; // I never define `addon` before this line, so this cause: ReferenceError: "addon is not defined". We aren't aware of this mistake.
// Some more code
// Some more code
// Some more code
// Some more code
debugger; // Here we want to stop execution and inspect, some other stuff. Remember that we aren't aware of earlier mistake.
What we would expect, that in console error about Reference error will appear, but it doesn't. Console get silent, and we don't know why our debugger keyword doesn't work.
This kind of silent error, happened to me when I misspell variable name. In result couldn't figure out what's wrong.
The errors in the content script are not reported in the tab's Web Console due to Firefox bug 1410932, which is not fixed (as of Firefox 79, released on 2020-07-28).
I listed possible workarounds in another answer:
use try..catch with logging,
check the Browser Console (which does show errors from the content script)
use the Debugger's "pause on exceptions" option.
Content scripts are executed in webpage, So as you know to see it's output you should open up console menu in that specific web page (ctrl+shift+e then go to console).
But if something is wrong with content script and cause it to throw exception, The error log would be shown in debug area of your extension in: about:debugging
I think the reason is content scripts are treated like extra frame for webpage and their error is shown there.
FF25.0, Fedora 18.
This just keeps going round in circles. The staging extension installs, and parts of it are active as the extension modifies a bit of the dom (I think even the background script is running too as the local storage is initialized). Not all of the extension works, such as the sidebar and other dom injection that should run on page load. But the debug mode page in crossrider fails to recognise the running extension.
I suspect this is due to a bug in my code but there appears to be no way to debug it. When I commented out the sidebar, it still showed briefly after another install, which makes me suspect a proxy/cache is getting in the way but adding an extra GET argument on the extension URL didn't help. I've tried adding debugger to extension.js. The console is empty. No errors are reported by firebug. The extension works fine in chrome, and I really don't want to go back to a blank extension and try adding bit by bit till it fails. There must be a simpler way such as making firefox just say, "here's your problem, right on line number X". Any ideas?
[EDIT]
After turning on some debug options, I've got errors in the console, but clicking on the offending file/line number just opens the "Source of:..." window. In google chrome I get the file in the debugger, can hit break points, refresh and catch the error as it happens. Better yet, how about a "break-on-exceptions" option that both works but also actually works.
[EDIT]
I finally got the Browser Debugger working. The first error is a NS_ERROR_XPC_BAD_OP_ON_WN_PROTO.
Well, to start actually getting messages you need to set some flags in "about:config" listed here: Setting_up_extension_development_environment
I'll copy a few...
javascript.options.showInConsole = true (this was already on for me)
browser.dom.window.dump.enabled = true
javascript.options.strict = true (there's also a debug version I turned on too)
devtools.chrome.enabled = true (nothing to do with google chrome)
devtools.debugger.remote-enabled = true (the important one, allowing Firefox->Web Developer->Browser Debugger, make sure to allow the remote debugger otherwise it undoes the config change)
devtools.errorconsole.enabled = true
extensions.logging.enabled = true
It looks like quite a few options have been removed too. This has at least got me started.
[EDIT]
This answer also mentions the "Web Developer->Browser Debugger" (which is currently blank - "no sources" - I have no idea) and "Web Developer->Browser Console" windows (just seems to have the same output as the in-window console).
Throw a giant try/catch around ALL your extension code. At least this allows the crossrider "staging" extension to install and be recognised.
Print the exception (I assume all the stupid about:config stuff has to be set for this to work)
appAPI.ready(function($) {
try {
...rest of extension code
}
catch (e)
{
console.log("#################", e);
}
}
Locate the error in the console, and click on the [object exception]. Note the line number (it won't be correct as other code is injected). Also note we've managed to print an exception and firefox failed to break on it. FFFFFFFFFFFFFFFFFFFF
Add some newlines approximately in the middle of the code.
Reload. Note the line number. If it's changed the error is after the newlines. If not the error is before.
Repeat from step 4 until the error is found.
Take a moment to reflect on the stupidity of this process. (this isn't exactly a comment directed at crossrider, more at the severe lack of simple web development tools and APIs currently available)
I get this error message in Firebug:
Permission denied for <http://googleads.g.doubleclick.net> to call method Location.toString
It comes from this page:
http://www.comehike.com/outdoors/trees/add_spotted_trees.php?hike_id=108
The login credentials for this page are:
test#comehike.com | password
When I look at it in Firebug, using the Console --> Errors view, I see that error first, followed by a number of other errors, but I can't really double-click on the errors to see what line they are coming from, and the line isn't written there as far as I can see. There are some line references on the page, but they lead to pretty random spots.
Any ideas how to debug such a thing? I am new to JS and FireBug.
Thanks,
Alex
The Location.toString error is usually due to some ad-serving javascript code, trying to get a text version of the current page's location. Firefox denies access to this information to 3rd party scripts by default, since 3rd party scripts should have no business knowing exactly what page you're on.
Basically it's an attempt by ad networks to work around some clients not sending referers, by trying to grab the location data directly.
In firebug under the "bug" icon (upper left when open) you'll see a pause button (in the console tab). This will cause the page to stop loading and jump to the exact error in the script.
However, when I visited the page I do not see any errors.
body' onLoad is:
initializeTreeHike( , );
You don't need to use comma if you wish to pass no parameters to the function.
When I follow the provided link in Firefox 4.0 with Firebug 1.7, I don't receive the error you encountered. What I do receive however is the following:
Syntax error: initializeTreeHike( , );
It appears this is coming from line 326 in add_spotted_trees.php in the following line:
<body onload="initializeTreeHike( , );"
Perhaps you meant to pass in empty strings as parameters?
I am currently working on a website. For debugging reasons, i chose the view source option of firefox v3.6b4. Then i clicked on javascript link eg something like this from within the source page:
<script type="text/javascript" src="./dealer/dialog/jquery-1.3.2.min.js"></script>
Guess what, it showed me below message:
<HTML>
<HEAD>
<TITLE>404 Not Found</TITLE>
</HEAD>
<BODY>
<H1>Not Found</H1>
The requested document was not found on this server.
<P>
<HR>
<ADDRESS>
Web Server at souq4cars.com
</ADDRESS>
</BODY>
</HTML>
<!--
- Unfortunately, Microsoft has added a clever new
- "feature" to Internet Explorer. If the text of
- an error's message is "too small", specifically
- less than 512 bytes, Internet Explorer returns
- its own error message. You can turn that off,
- but it's pretty tricky to find switch called
- "smart error messages". That means, of course,
- that short error messages are censored by default.
- IIS always returns error messages that are long
- enough to make Internet Explorer happy. The
- workaround is pretty simple: pad the error
- message with a big comment like this to push it
- over the five hundred and twelve bytes minimum.
- Of course, that's exactly what you're reading
- right now.
-->
What is happening there? I am unable to open the JS file !
Firefox showing a message about microsoft and IE !!!
The path to your JavaScript file is most likely incorrect.
Thus, you are (rightly) getting your provider's standard 404 error file.
That error file contains a comment in order to make it larger than 512 bytes.
That is, as the comment points out, because Internet Explorer does not display custom 404 error pages if they are smaller than 512 bytes (source). If they are smaller, it will display its built-in "the page you were looking for could not be found" message.
Correct the path to your JavaScript file and you should be fine.
Sadly, there is no automated mechanism that warns about Javascript files that were referenced to but could not be loaded (I still don't understand why - a browser that can throw Javascript errors could also complain about a missing file). Firebug's net tab is a great way of finding out whether a JavaScript file has been loaded or not, I can recommend that very much for development.
Most likely is that the server is rejecting requests to the URL without the expected HTTP REFERRER header. This will prevent people from grabbing files directly, rather than being referenced by the expected file.
Try to spoof the referring header and attempt to see if you get the same response.
It's either that or the JavaScript path does not actually exist, thus throwing a 404 error.
This message is just so that Internet Explorer will allow the massage through, instead of showing its own message. The "not found" message simply means that the document (website) you are trying to load has a bad file adress. That text is meaningless, it is only extra data in case you are using IE