rv = new Array();
	rv[1]=8000;
	rv[2]=7000;
	rv[3]=8000;
	rv[4]=6000;
	rv[5]=8000;
valve12 = new Array();
	valve12[0] = 75;
	valve12[1] = 50;
	valve12[2] = 50;
	valve12[3] = 60;
	valve12[4] = 70;
	valve12[5] = 160;
valve34 = new Array();
	valve34[0] = 100;
	valve34[1] = 70;
	valve34[2] = 65;
	valve34[3] = 70;
	valve34[4] = 70;
	valve34[5] = 70;
function reCal(){
	var m,btu,nr;
	m = d.elements['unit_of_m'][0].checked ==true?12:304.8;
	for(i=0;i<15;i++){
	if(d.elements['rlength['+i+']']){
	if(VN(d.elements['rlength['+i+']'].value) &&
   VN(d.elements['rwidth['+i+']'].value) &&
   VN(d.elements['rheight['+i+']'].value) &&
   d.elements['styles['+i+']'].value!='0' 
   ){
	
	 btu = (d.elements['rlength['+i+']'].value/m) * (d.elements['rwidth['+i+']'].value/m) * (d.elements['rheight['+i+']'].value/m) * 6;
 
btu = Math.round(btu);
tmp_btu = btu;
document.getElementById('btu_display'+i).innerHTML = btu;
d.elements['btu['+i+']'].value = btu;
nr = Math.ceil(tmp_btu/rv[d.elements['styles['+i+']'].value]);
document.getElementById('no_rads'+i).innerHTML = nr;
d.elements['numberrads['+i+']'].value = nr;
	}
	}
	}
}
function VN(val){
var re_num= /^([0-9]){1,6}$/;
	if(val!=''){
	if(!re_num.test(val)){
	alert('Only whole numbers are allowed.');
	return false; 
	} else {
	return true;
	}
	}
}
function CalculateBTU(obj,i){
var m,btu,nr;
if(d.elements['unit_of_m'][0].checked ==true || d.elements['unit_of_m'][1].checked ==true){
m = d.elements['unit_of_m'][0].checked ==true?12:304.8;
} else {
alert('Please select a unit of measurement eg inches or mms');
return false;
}

if(VN(d.elements['rlength['+i+']'].value) &&
   VN(d.elements['rwidth['+i+']'].value) &&
   VN(d.elements['rheight['+i+']'].value) &&
   d.elements['styles['+i+']'].value!='0' 
   ){


 btu = (d.elements['rlength['+i+']'].value/m) * (d.elements['rwidth['+i+']'].value/m) * (d.elements['rheight['+i+']'].value/m) * 6;
 
btu = Math.round(btu);
tmp_btu = btu;
document.getElementById('btu_display'+i).innerHTML = btu;
d.elements['btu['+i+']'].value = btu;
nr = Math.ceil(tmp_btu/rv[d.elements['styles['+i+']'].value]);
document.getElementById('no_rads'+i).innerHTML = nr;
d.elements['numberrads['+i+']'].value = nr;
   }
}
function CalcValve(obj,i){
var j,t,t2=0;
if(d.elements['rv12['+i+']'])
t = valve12[i]*d.elements['rv12['+i+']'].value;
if(d.elements['rv34['+i+']'])
t+= valve34[i]*d.elements['rv34['+i+']'].value;

if(t>0){
document.getElementById('valvecostdisplay'+i).innerHTML = '&pound;'+t;
} else {
document.getElementById('valvecostdisplay'+i).innerHTML = '';
}
d.elements['valvecost['+i+']'].value = t;
for(j=0;j<6;j++){
if(d.elements['valvecost['+j+']'])
t2+= parseInt(d.elements['valvecost['+j+']'].value);
}
document.getElementById('grandtotal').innerHTML = '&pound;'+t2;
d.elements['gtotal'].value = t2;

}
function Validate(){
var str='';
	if(d.elements['cname'].value==''){
	str += 'Please enter your Name\n';
	}
	if(d.elements['address1'].value==''){
	str += 'Please enter your Address\n';
	}
	if(d.elements['town'].value==''){
	str += 'Please enter your Town/City\n';
	}
	if(d.elements['country'].value==''){
	str += 'Please enter your Country\n';
	}
	if(d.elements['postcode'].value==''){
	str += 'Please enter your Postcode\n';
	}
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(!filter.test(d.elements['email'].value)){
	str += 'Please enter a valid Email Address\n';
	}
	if(str!=''){
	var h = 'Please complete the form fields indicated below:\n\n';
	alert(h+str);
	return false;
	} else {
	return true;
	}
}
window.onload = function(){
d = document.forms['btu'];
}