function htmlRef(element) {
	if (element)
	{
		if (document.getElementById) {
			if (document.getElementById(element)) {
				var ref = document.getElementById(element);
			}
		} else if (document.all) {
			if (document.all[element]) {
				var ref = document.all[element];
			}
		} else if (document.layers) {
			if (document.layers[element]) {
				var ref = document.layers[element];
			}
		} else {  }
		return ref 
	}
	else
	{return null;}
}

function update_quantity(id)
{
	if ( document.cart_form.elements['quantity['+id+']'].value>0 )
	{
		quantity_array[id]=document.cart_form.elements['quantity['+id+']'].value;
		//alert('document.cart_form.elements[quantity['+id+']].value ' + document.cart_form.elements['quantity['+id+']'].value);
		
		if ( document.cart_form.elements['quantity['+id+']'].value<=1 )
		{
			document.cart_form.elements['subtract['+id+']'].src="/images/version1/quantity-subtract-disabled.gif";
		}
		else if ( document.cart_form.elements['quantity['+id+']'].value>=2 )
		{
			document.cart_form.elements['subtract['+id+']'].src="/images/version1/quantity-subtract.gif";
		}
		
		on_change_quantity(id);
	}
	else
	{
		document.cart_form.elements['quantity['+id+']'].value=quantity_array[id];
	}
}

function increase_quantity_(id)//will only work for large cart
{
	quantity_array[id]=(quantity_array[id]*1)+1;
	document.cart_form.elements['quantity['+id+']'].value=quantity_array[id];
	
	if ( document.cart_form.elements['quantity['+id+']'].value>=2 )
	{
		document.cart_form.elements['subtract['+id+']'].src="/images/version1/quantity-subtract.gif";
	}
	
	on_change_quantity(id);
}

function decrease_quantity_(id)
{
	if ( quantity_array[id]>1 )
	{
		quantity_array[id]=(quantity_array[id]*1)-1;
		document.cart_form.elements['quantity['+id+']'].value=quantity_array[id];
		
		if ( document.cart_form.elements['quantity['+id+']'].value<=1 )
		{
			document.cart_form.elements['subtract['+id+']'].src="/images/version1/quantity-subtract-disabled.gif";
		}
	
		on_change_quantity(id);
	}
}

function on_change_quantity(id)
{
	var tempstring1=price_array[id]*quantity_array[id];
	htmlRef('price['+id+']').innerHTML=currency_symbol+tempstring1.toFixed(2);
	
	//calculate new subtotal
	var subtotal = 0;
	var vattotal = 0;
	var total = 0;
	for (i=0;i<product_array.length;i++)
	{
		var product_array_i = product_array[i];
		subtotal = subtotal + quantity_array[product_array_i]*price_array[product_array_i];
		
		var tempstring2=price_array[product_array_i]*0.175;
		vattotal = vattotal + (tempstring2.toFixed(2))*quantity_array[product_array_i];
	}
	vattotal = vattotal + shipping_vat;
	total = subtotal + shipping_price + vattotal;
	
	//subtotal = subtotal.toFixed(2);
	//vattotal = vattotal.toFixed(2);
	//total = total.toFixed(2);
	
	// round numbers in case javascript decided to add on a tiny fraction
	htmlRef('subtotal').innerHTML=currency_symbol+subtotal.toFixed(2);
	htmlRef('vattotal').innerHTML=currency_symbol+vattotal.toFixed(2);
	htmlRef('total').innerHTML=currency_symbol+total.toFixed(2);
	
	htmlRef('update_cart').className='submit';//was submit_highlight
	htmlRef('update_cart').disabled=false;
}

function unload_alert()
{
	alert('All changes made on the current cart page will be lost.');
}