Javascript array with custom variable indexing

I think what you want is:

var indexID = 5;
var temp = {};
temp[indexID] = "stuff"

Yes, just use square brackets notation:

var temp = {};
temp[indexID] = [];

Also pay attention to the fact that temp is an object, and not an array. In JavaScript all associative arrays (or dictionaries) are represented as objects.

MORE: http://www.jibbering.com/faq/faq_notes/square_brackets.html#vId