// begin
function ValidateFields() {
	// variables and innitialization
	var str, result;
	str = "";
	result = true;
	
	// proof form field entries
	if (document.form_invoice.item_number.value == "") {
		str += "Invoice Number: \n";
		result = false;
	}
	if (document.form_invoice.amount.value == "") {
		str += "Amount: \n";
		result = false;
	}
	
	// Error window header		
	if (result == false) {
		alert("The following are required fields:\n_____________________________\n\n" + str + "\nIf you are uncertain of your invoice\nnumber or amount due, please call\n(516) 448-0549.");
		return false;
	}	
	return true;
}
// end