function calculateExp() {
	var mortexp = new Number(document.ratio.mortexp.value);
	var credexp = new Number(document.ratio.credexp.value);
	var autoexp = new Number(document.ratio.autoexp.value);
	var otherexp = new Number(document.ratio.otherexp.value);

	var totexp = mortexp + credexp + autoexp + otherexp;
	
	if(isNaN(totexp)) {
		alert("All entries must be numbers");
		document.ratio.totexp.value = "";
	}
	else
		document.ratio.totexp.value = totexp;
	
}

function calculateInc() {
	var salinc = new Number(document.ratio.salinc.value);
	var extinc = new Number(document.ratio.extinc.value);	
	var othinc = new Number(document.ratio.othinc.value);
	var alinc = new Number(document.ratio.alinc.value);
	
	var totinc = salinc + extinc + othinc + alinc;
	
	if(isNaN(totinc)) {
		alert("All entries must be numbers");
		document.ratio.totinc.value = "";
	}
	else
		document.ratio.totinc.value = totinc;
}

function calculateRat() {

	var totexp = new Number(document.ratio.totexp.value);
	var totinc = new Number(document.ratio.totinc.value);	
	
	if(totexp=="" || totinc=="")
	alert("You have not completed the form");
		
	var rat = totexp / totinc;
	document.ratio.totexptotinc.value = Math.round(100 * rat) + "%";
}