function isDigit (c) { 
	return ((c >= "0") && (c <= "9") || (c == "."))
}
function ValidateForm() {
	var f = document.forms[0];
	var miles = f.miles.value;
	var mpg = f.mpg.value;
	var commute = f.commute.value;
	var childcare = f.childcare.value;
	var commutetime = f.commutetime.value;
	var labor = f.labor.value;	
	var color = "#000000";
	var msg = "An invalid character has been detected.  Please correct before calculating savings"	
	for (var i=0; i < f.elements.length; i++) {
		if (f.elements[i].type == "text") {
			var fieldval = f.elements[i].value;
			for (var y = 0; y < fieldval.length; y++) {
				var c = fieldval.charAt(y);
				if (!isDigit(c)) { 
					alert("An invalid character has been detected. Please correct before calculating savings");
					eval("document.forms[0]."+f.elements[i].name+".focus()");
					return;
				}
			}
		}
	}
	if (miles == "" && mpg !="") { 
		alert("Please enter the miles for your round-trip commute"); 
		f.miles.focus();
		return;
	}
	
	if ((miles != "" && Number(miles) != Number(0)) && Number(mpg)==Number(0)) {
		alert("Miles per gallon cannot be zero if round-trip commute is not zero");
		f.mpg.focus();
		return;
	}
	ShowResult(miles, mpg, commute, childcare, commutetime, labor, color)
}