Question

Hi I am trying to print out the first element and the element attached to that element in an array. I am getting ‘helloh’ in firefox and ‘helloundefined’ in IE. Does anyone know why this isn’t working.

Here is a jsfiddle.. http://jsfiddle.net/ZtuAu/

<script language=javascript> 
var test = new Array();
test[0] = new Array();

test[0] = "hello";
test[0][0] = "world";
document.write(test[0] + test[0][0]);
</script>

Answer 1

You have an array

var test = new Array();

If you want to insert an item into it, use push

test[0] = new Array(); // not this way
test.push(new Array()); // this way

Because you want the array to update its length property etc.

So, you do this:

test[0] = new Array();
test[0] = "hello";

You’re assigning the same thing twice, so naturally, only the second assignment holds. So we have

test[0] == "hello"

Then, in FireFox, you can use [] to access any character of the string

test[0][0] == "hello"[0] == "h"

Apparently, in IE you cannot do that, so you get undefined.