function subtotal(count)
{
	var total	= 0;
	var price	= 0;
	var amount	= 0;
	
	for(var i = 1; i < (count + 1);i++)
	{
		price	= document.getElementById("price_" + i).innerHTML;
		amount	= parseInt(document.getElementById("amount_" + i).value);

		if(isNaN(amount))
		{
			amount											= 0;
			document.getElementById("amount_" + i).value	= amount;
		}
		else
		{
			document.getElementById("amount_" + i).value = parseInt(document.getElementById("amount_" + i).value);
		}
		
		total = Math.round((total + (price*amount))*100)/100;
	}

	document.getElementById("subtotaal").innerHTML = total.toFixed(2);
}