function checkQuantity() {
	var valid = false;
	if(document.getElementById('quantity').value == "") {
		document.getElementById('quantityMsg').innerHTML = '<img src=\"/images/required.gif\" alt=\"Required Field\" title=\"Required Field\" style=\"margin-top:3px;\" />';
		document.getElementById('errorMsg').innerHTML = "<p class=\"error\">Please enter a quantity (minimum 500 litres).</p>";
		document.quote.quantity.style.background="#FFA8B0";
		document.forms.quote.quantity.focus()
		return false;
	}
	
	if(document.getElementById('quantity').value < 500) {
	document.getElementById('quantityMsg').innerHTML = '<img src=\"/images/error.gif\" alt=\"Error: Quantity must be at least 500 litres.\" title=\"Error: Quantity must be at least 500 litres.\" style=\"margin-top:3px;\" />';
	document.getElementById('errorMsg').innerHTML = "<p class=\"error\">Please enter a quantity (minimum 500 litres).</p>";
	document.quote.quantity.style.background="#FFA8B0";
	document.forms.quote.quantity.focus();
	return false;
	}

	if(document.getElementById('quantity').value > 14000) {
	document.getElementById('quantityMsg').innerHTML = '<img src=\"/images/error.gif\" alt=\"Error: Quantity must be less than 14000 litres.\" title=\"Error: Quantity must be less than 14000 litres.\" style=\"margin-top:3px;\" />';
	document.getElementById('errorMsg').innerHTML = "<p class=\"error\">Please enter a quantity with a maximum of 14000 litres.</p>";
	document.quote.quantity.style.background="#FFA8B0";
	document.forms.quote.quantity.focus();
	return false;
	}

	if(document.getElementById('quantity').value > 499 && document.getElementById('quantity').value <= 14000) {
	document.quote.quantity.style.background="#FFFFFF";
	document.getElementById('quantityMsg').innerHTML = '<img src=\"/images/tick.gif\" alt=\"OK!\" title=\"OK!\" style=\"margin-top:3px;\" />';
	document.getElementById('errorMsg').innerHTML = "";
	valid = true;
	}
}