function checkQuantity(i)
{
	id = document.getElementById("txtQuantity"+i);
	valid = true;

	if(id.value != '')
		for(j=0;j<id.value.length;j++)
		{
			if(!(id.value.charCodeAt(j) >=48 && id.value.charCodeAt(j) <=57))  // 48 to 57
				valid = false;
		}

	if(id.value == '' || !valid)
	{
		id.focus();
		document.getElementById("divQuantity"+i).style.display = "block";
	}
	else
	{
		document.getElementById("txtQuantity").value = id.value;
		document.frmPromo.submit();
	}
}