//	remove duplicate values in array
Array.prototype.unique = function ()
{
	var n = this.length;
	for (var y = 0; y < n; ++y)
	{
		for (var z = y + 1; z <= n; ++z)
		{
			if (this[y] == this[z])
			{
				this.splice (z, 1);
			}
		}
	}
};

function toCompare (itID)
{
	var compare = $.cookie("compare");
	var ids = Array ();
	if (typeof compare != "object")
	{
		ids = compare.split (" ");
	}

	if ($("#comp_" + itID).attr ("checked"))
	{
		ids.push (itID);
	} else
	{
		for (var i = 0, n = ids.length; i < n; i++)
		{
			if (ids[i] == itID)
			{
				ids.splice (i, 1);
			}
		}
	}
	ids.sort ();
	ids.unique ();
	compare = ids.join (" ");

	$.cookie ("compare", compare, {expires: 365 * 24});
}