Why does Firebug not show an 'Uncaught Type Error' for undefined properties?

Question

I typically use Firebug for development, but lately some of my scripts have been failing silently. After hours of tracking down the error, I discovered I was attempting to get a property of an undefined variable. The console had no errors, the page just "broke". However, in the Chrome DevTools it correctly identifies the error. here is a simple test case:

var x = {
    i: {a:1,b:2}
}

In Chrome you get

console.log(x.i.a); //1
console.log(x.iii.a); //Uncaught TypeError: 
                      //Cannot read property 'a' of undefined 
console.log('finished'); //does not execute

In Firebug you get

console.log(x.i.a); //1
console.log(x.iii.a); //(nothing)
console.log('finished'); //does not execute

See this Fiddle.

So in a real script, when this happens, I have a seriously hard time tracking down where my script is halting, and I have to add a huge amount of console logging just to narrow down the error.

Is this a bug, or somehow the intended behavior of Firebug, or maybe there's a setting I can tweak? I'm using 2.0.3.

Answer 1

You need to check the option Show JavaScript Errors within the Console panel options menu.

As you can see, this makes the console correctly log the error message.