Question

A small version of my script would be this:

var x = null;
for(var i=0; i<x.length; i++)
{
    //do stuff
}

I noticed (by doing some ‘alert’ debugs) that my script halts when evaluating x.length. Even when i try to print it in an alert, the script stops.

The idea is that somethimes my x variable is an array, sometimes is null.

Of course, I am a beginner, so probably i’ve done something stupid. No errors appear in my Firefox 6 error console.

Thanks a lot for any ideas!

Answer 1

try

var x = null;
for(var i = 0; x && i < x.length; i++) {
    //do stuff
}

This will first check whether x is not null. If x is null, for will not run. If it is not null, for will run as usual.