function validNum(source) {
		if ((source.value == "") || (isNaN(source.value) == false)) {
			return true
		} else {
			alert("Please enter an actual number")
			source.value = ""
			source.focus()
			event.returnValue=false;
			return false
		}
	}
	
	function sumCosts(source) {
		validNum(source) 
				
		Parts1 = (document.WarrantyClaim.Parts1_Amount.value)*(document.WarrantyClaim.Parts1_Unit_Cost.value);
		Parts2 = (document.WarrantyClaim.Parts2_Amount.value)*(document.WarrantyClaim.Parts2_Unit_Cost.value);
		Parts3 = (document.WarrantyClaim.Parts3_Amount.value)*(document.WarrantyClaim.Parts3_Unit_Cost.value);
		Parts4 = (document.WarrantyClaim.Parts4_Amount.value)*(document.WarrantyClaim.Parts4_Unit_Cost.value);
		
		Parts1 = Math.round(Parts1*100)/100;
		Parts2 = Math.round(Parts2*100)/100;
		Parts3 = Math.round(Parts3*100)/100;
		Parts4 = Math.round(Parts4*100)/100;
		
		document.WarrantyClaim.Parts1_SubTotal.value = Parts1;
		document.WarrantyClaim.Parts2_SubTotal.value = Parts2;
		document.WarrantyClaim.Parts3_SubTotal.value = Parts3;
		document.WarrantyClaim.Parts4_SubTotal.value = Parts4;
		
		document.WarrantyClaim.Parts_Total.value = Math.round((Parts1+Parts2+Parts3+Parts4)*100)/100;

		Labor1 = (document.WarrantyClaim.Labor1_Hours.value)*(document.WarrantyClaim.Labor1_Rate.value);
		Labor2 = (document.WarrantyClaim.Labor2_Hours.value)*(document.WarrantyClaim.Labor2_Rate.value);
		Labor3 = (document.WarrantyClaim.Labor3_Hours.value)*(document.WarrantyClaim.Labor3_Rate.value);
		Labor4 = (document.WarrantyClaim.Labor4_Hours.value)*(document.WarrantyClaim.Labor4_Rate.value);

		Labor1 = Math.round(Labor1*100)/100;
		Labor2 = Math.round(Labor2*100)/100;
		Labor3 = Math.round(Labor3*100)/100;
		Labor4 = Math.round(Labor4*100)/100;
		
		document.WarrantyClaim.Labor1_SubTotal.value = Labor1;
		document.WarrantyClaim.Labor2_SubTotal.value = Labor2;
		document.WarrantyClaim.Labor3_SubTotal.value = Labor3;
		document.WarrantyClaim.Labor4_SubTotal.value = Labor4;

		document.WarrantyClaim.Labor_Total.value = Math.round((Labor1+Labor2+Labor3+Labor4)*100)/100;	
		
		document.WarrantyClaim.Total_Requested.value = Math.round((Parts1+Parts2+Parts3+Parts4+Labor1+Labor2+Labor3+Labor4)*100)/100;
	}