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.
Related
I just installed Sentry for a client-side JavaScript app using the standard code snippet they provided. How do I test that it's working properly? I've tried manually throwing an error from my browser console and it didn't appear in Sentry. Is there any documentation on the right way to do this?
Verify (newer)
myUndefinedFunction();
Verifying Your Setup (older)
Sentry.captureException(new Error("This is my fake error message"));
https://docs.sentry.io/platforms/javascript/?platform=browser#verifying-your-setup
May be worth double-checking your setup (or updating) and config too.
The browser console can not be used as it is sandboxed. A simple trick is to attach the code to an HTML element like this:
<h1 onClick="throw new Error('Test')">
My Website
</h1>
And click on the heading afterwards.
This can be done in the browser inspector and so your source code doesn't have to be modified.
One way to generate an error in Sentry is to call a function that is not defined.
Note: This cannot be done in the console - it must be in the code.
Try adding this to your code (taken from the docs):
myUndefinedFunction();
If your code build doesn't allow this due to tests/linting you might be able to use:
window.myUndefinedFunction()
You should then see error in your browser console and in the Sentry dashboard.
Have a read of the Docs for more info.
Raven.captureMessage('Broken!') is a good place to start (also pulled from Sentry docs). If that fails to send, the Raven client isn't being initiated.
If you can't or don't want to use an undefined function to test Sentry is sending errors, you can also use the Debugger in Chrome's DevTools by:
Adding a breakpoint in your code e.g. for a click event handler
Trigger that event e.g. click a button
When the breakpoint hits in the console, set a function/variable that is needed for execution to undefined
Press play/continue in DevTools to then see the Error output
e.g.
1: function onClick() {
2: api.sendSomeEvent();
3: }
Add a breakpoint in the body of the onClick event handler (Line 2), trigger the event. When execution is paused: in your console enter something like api = undefined and hit enter to update the state. Then continue execution (click the play button), where you should see an error (ala api is undefined) that Sentry should then send for you.
Note: this works for any environment, though you may need to be clever with finding your events in minified code ;)
For Mozilla WebExtensions, how do I get Javascript errors to show up in the console log?
I'm opening the developer tools for the appropriate tab. I run the
code below in a WebExtension content script.
"use strict"
console.log("Load start.");
foofoofoo; // ***TEMP*** force error
The message "Load start." appears in the console for that tab, but there's no message for the error from the next line. I never seem to get any Javascript error messages from add-ons in the console. I can see them if I step through in the debugger, but can't just get an ordinary Javascript error message.
The "Browser console" (CTL-SHIFT-J) shows the Javascript error messages from a content script, but the Developer Tools console, even though it will show log messages from an add-on content script, does not.
This does not appear to be documented.
In addition to the browser console that you already discovered and the browser toolbox you can find addon-specific debuggers under about:debugging.
Which debugger to use for which context is documented on the MDN article WebExtensions/Debugging
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)
How come I get this message from Firefox Web Console
The Web Console logging API (console.log, console.info, console.warn, console.error) has been disabled by a script on this page
The same webpage can print messages in Chrome Console but not Firefox. I opened the same webpage in another computers' Firefox (don't know what version) Web Console can print messages. My Firefox version is the latest, 8.0.
This happens when the page itself defines a global variable called console, for example. If the page is browser-sniffing to decide whether to define it, the behavior could differ in different browsers.
In the case of Firefox it also happens when Firebug is installed and its console is enabled, since that overrides the default window.console.
I had the same exact error message, and once I removed firebug, it went away.
I'm not saying you should remove firebug, I love firebug, but that is most probably the source of the error for you as well. One more note, the error was still there even if firebug was turned off (disabled) for that particular page.
Here is a JavaScript workaround I used to restore console API after it was set to empty function by a script on the page (works in Firefox 46, tested in Firebug and in greasemonkey script):
function restoreConsole() {
var i = document.createElement('iframe');
i.style.display = 'none';
document.body.appendChild(i);
window.console = i.contentWindow.console;
i.parentNode.removeChild(i);
}
More info and credentials: Restoring console.log()
Right click over firebug console tab and uncheck "enabled" option (the first one).
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?