CODEWITHSUNDEEP
javascriptjqueryfirebug
Teekin
Teekin

Reputation: 13259

Stop suppressing JavaScript errors

I'm using Firebug to view JavaScript errors. But I'm also using jQuery. For some reason, I never see JavaScript errors when using jQuery and this is one of the biggest problems with working with jQuery in the first place.

There's no particular code to show, just imagine alert(areareg); where areareg is undefined or any sort of JavaScript error, and Firebug won't tell me about it. The JavaScript will simply fail without warning or notification of any sort. This is always the case, in any project where I've used jQuery and it's the only reason I don't like jQuery; because it's notoriously difficult to debug when something goes wrong.

For some reason I've even had trouble finding this question raised online, let alone answered. But I figured I'd give it a try here:

  1. Is there any way to make jQuery stop suppressing error messages?
  2. Am I the only one in the world who has always had this problem with jQuery?

EDIT: I use both Firefox (with Firebug) and Chrome, and I only use the non-minified version of jQuery. Still, I have never in my entire life seen a jQuery error message of any kind, neither useful nor useless, nor in fact normal JavaScript errors, when using jQuery.

Upvotes: 13

Views: 2290

Answers (4)

user56reinstatemonica8
user56reinstatemonica8

Reputation: 34074

I've run into this problem several times. It's quite inconsistent and hard to replicate, sometimes it seems related to version issues. Settings rarely seem to make a difference, though "Break on next" sometimes (not always) identifies errors that otherwise slip through.

One thing I've noticed is, it tends to happen for code that is triggered inside a callback function, e.g. from a UI event or from an AJAX call. Sometimes Firefox / Firebug will behave like other browsers and show errors in the console, sometimes it gives nothing at all even for incredibly clear-cut cases like:

console.log('something'); // Shows up in console fine
fail  // Other browsers give undefined variable error, Firefox gives nothing
console.log('something else'); // Never reached, so silent error clearly happens

The best approach I've found to this is:

  • Once you've found a no-show error, work back using console.trace() until you reach a point where inside a function, the error is hidden, outside, it shows, adding some code snippet like:

     console.trace();
 fail // cause the error, look out for a trace followed by nothing

  • If it's an AJAX call, manually add a basic error handler, because for some reason Firefox/Firebug is losing the default:

     $.ajax({
   error: function(a,b,c){
     throw c;
   }, 
   other: '...settings'
 }
    • If it's something you can't add an error handling function to, wrap it in a try... catch, for example:
     try {
   // whatever the code is within which there are no errors
 } catch( err ){
   throw err;
 }

This should be enough to catch all errors where-ever they are within the scope where Firefox is losing them. Beware of cases where you have a callback within a callback though, you might need to do this twice...

Upvotes: 0

Dovev Hefetz
Dovev Hefetz

Reputation: 1456

I am having the same problem in FF 18. I am using JSF and JQuery, though it happens even for plain JS code on the page. I intentionally put javascript code that should throw a syntax error without a word in Firebug. FF 18 has its own built-in console that looks similar to firebug. When I disabled the firebug plug-in the console.log messages started showing up. However, the errors are still not showing up. I just tried Chrome and the errors do appear there.

Upvotes: 1

Sina Fathieh
Sina Fathieh

Reputation: 1725

I use google Chrome for my debugging, and it's pretty good, it shows all the jquery errors as well (as Alfred said, if you use minified version, you wont get any meaningful name in your errors, so it's better to use the raw source)

Upvotes: 2

Pointy
Pointy

Reputation: 413702

Well, despite your impression, jQuery itself doesn't do anything to "suppress" error messages. Now, Firefox does tend to throw away certain kinds of exceptions, notably like what you describe. I often find that wrapping a whole Javascript block in a try ... catch with an alert call should an exception happen is a useful way to deal with it, but it's still irritating.

Upvotes: 3

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