function getObject(obj) {var theObj;
if (document.all) {if (typeof obj == "string") {return document.all(obj)} else {return obj.style}}
if (document.getElementById) {if (typeof obj == "string") {return document.getElementById(obj)} else {return obj.style}}return null}

function calculateCosts(){
nMsqr = getObject("msquare").value;
nMsqr = nMsqr.replace(" ","");
getObject("msquare").value = nMsqr;
if (isNumeric(nMsqr)){
  populateResults(nMsqr); 
}else{
  alert ("Floor area must be numerical.");  
}
}

function populateResults(nMsqr){
nBudget = nMsqr*1450;
getObject("budget").innerHTML = "£"+addCommas(nBudget.toFixed(2));

nPlanning = nBudget*1.45/100;
getObject("planning").innerHTML = "£"+addCommas(nPlanning.toFixed(2));

nDesign = nBudget*0.03;
getObject("design").innerHTML = "£"+addCommas(nDesign.toFixed(2));

nTender = nBudget*0.0045;
getObject("tender").innerHTML = "£"+addCommas(nTender.toFixed(2));

nSupervision = nBudget*0.045;
getObject("supervision").innerHTML = "£"+addCommas(nSupervision.toFixed(2));


}


function addCommas(nStr)
{
	nStr += '';
	x = nStr.split('.');
	x1 = x[0];
	x2 = x.length > 1 ? '.' + x[1] : '';
	var rgx = /(\d+)(\d{3})/;
	while (rgx.test(x1)) {
		x1 = x1.replace(rgx, '$1' + ',' + '$2');
	}
	return x1 + x2;
}

function isNumeric(value) {
  if (value == null || !value.toString().match(/^[-]?\d*\.?\d*$/)) return false;
  return true;
}