var xmlHttp;

// function to run a php script to calculate the mortgage repayments
function calc()
{
	xmlHttp=GetXmlHttpObject()
	if (xmlHttp==null)
  	{
  		alert ("Your browser does not support AJAX!");
  		return;
  	}// end if

	var url = "includes/calculator.inc.php";
	url = url + "?principalLoan=" + document.myForm.principalLoan.value;
	url = url + "&interestRate=" + document.myForm.interestRate.value;
	url = url + "&durationYears=" + document.myForm.durationYears.value;

	xmlHttp.onreadystatechange=stateChanged;
  	xmlHttp.open('GET',url,true);
    xmlHttp.send(null);
}// end function calc()



// function to set the content of the object once the state has changed
function stateChanged()
{
	if (xmlHttp.readyState==4)
	{
		document.getElementById("output").innerHTML=xmlHttp.responseText;
		//document.myForm.time.value=xmlHttp.responseText;
	}// end if
}// end function stateChanged()



// set the XML HTTP Object
function GetXmlHttpObject()
{
	var xmlHttp=null;

	// ***************
	if (window.XMLHttpRequest)
	{
		// Mozilla, Safari, ...
        xmlHttp = new XMLHttpRequest();

		if (xmlHttp.overrideMimeType)
		{
            xmlHttp.overrideMimeType('text/xml');
        }// close if
    }else if (window.ActiveXObject) {
		// IE
        try
		{
        	xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
        }// end try

		catch (e)
		{
        	try
			{
                xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
            }// end try

			catch (e) {}// end catch
        }// end catch
    }// end if else
    // ****************



	return xmlHttp;
}// end function GetXmlHttpObject