function calc_area_cost(form1, form2){
	init(form1, form2);
	var a=0, b=0, c=0, d=0, e=0, f=0, blatt=0;
	a = mullop(form1.bed1W.value, form1.bed1L.value);
	form1.bed1A.value = a.toFixed(2);
	b = mullop(form1.bed2W.value, form1.bed2L.value);
	form1.bed2A.value = b.toFixed(2);
	c = mullop(form1.bed3W.value,form1.bed3L.value);
	form1.bed3A.value = c.toFixed(2);
	d = mullop(form1.loungeW.value, form1.loungeL.value);
	form1.loungeA.value = d.toFixed(2);
	e = mullop(form1.familyW.value, form1.familyL.value);
	form1.familyA.value = e.toFixed(2);
	f = mullop(form1.hallW.value, form1.hallL.value);
	form1.hallA.value = f.toFixed(2);
	blatt = a + b + c + d + e + f;
	form1.area.value = blatt.toFixed(2);
	form2.sqm15.value = "$"+(15 * blatt).toFixed(2);
	form2.sqm25.value = "$"+(25 * blatt).toFixed(2);
	form2.sqm35.value = "$"+(35 * blatt).toFixed(2);
	form2.sqm45.value = "$"+(45 * blatt).toFixed(2);
	form2.sqm55.value = "$"+(55 * blatt).toFixed(2);
	form2.sqm65.value = "$"+(65 * blatt).toFixed(2);
	form2.sqm75.value = "$"+(75 * blatt).toFixed(2);
}
function mullop(n1, n2){
	n1 = validate(n1);
	n2 = validate(n2);
	var a = (n1*n2);
	if(isNaN(a)){
		return 0;
	}
	return a;
}
function init(form1, form2){
	area = 0.00;
	form1.bed1A.value = 0;	
	form1.bed2A.value = 0;
	form1.bed3A.value = 0;
	form1.loungeA.value = 0;
	form1.familyA.value = 0;
	form1.hallA.value = 0;
	form1.area.value = area.toFixed(2);
	form2.sqm15.value = "$0.00";
	form2.sqm25.value = "$0.00";
	form2.sqm35.value = "$0.00";
	form2.sqm45.value = "$0.00";
	form2.sqm55.value = "$0.00";
	form2.sqm65.value = "$0.00";
	form2.sqm75.value = "$0.00";				
	return;
}

function validate(n){
	if(isNaN(n))
   {
     alert("\""+n+"\" Is an invalid data format.\n\nPlease use numbers only.");
	 return;
   }
   return n;
}