Detect existence of Mozilla's indexOf Array extension and implement if not available.

Array.indexOf.js

if(Array.prototype.indexOf === undefined)
{
	Array.prototype.indexOf = function(val)
	{
		for (var i = 0; i < this.length; i++)
		{
			if(this[i] == val)
				return i;
		}
		return -1;
	};
}