JavaScript Incrementing a number in an array

Question

I want to increment a value in a array when a link is pressed in JavaScript

i Used the following code

<script type="text/javascript">

 var i=0;
 var numbers = new Array();


 function go(val){

 numbers[i]=val;
 i++;

 alert(numbers[i]);

 }

</script>

Called the Function like this

<a href='javascript:go(1)' </a> 

but always the alert prompts me 'undefined'

Answer 1

The alert is correct -- before you do your alert, you incremented i. You're looking at the next element after the one you just entered.

After calling the method once, your array looks like this:

numbers[0] = 1;
numbers[1] = undefined;

and i == 1.

After calling it again, the array looks like:

numbers[0] = 1;
numbers[1] = 1;
numbers[2] = undefined;

and i == 2.

Hopefully you can see that this method will always alert undefined