var xmlhttp;
var id;

function runBOTNCalculation( form ) {
        xmlhttp = null;
        id = 'botn_results';
        
	if ( window.XMLHttpRequest ) {
                xmlhttp=new XMLHttpRequest()
        } else if ( window.ActiveXObject ) {
                xmlhttp = new ActiveXObject( "Microsoft.XMLHTTP" )
        }

	if ( xmlhttp != null ) {
		params = "price=" + encodeURI( form.price.value ) +
			 "&down=" + encodeURI( form.down.value ) +
			 "&mortgage_rate=" + encodeURI( form.mortgage_rate.value ) +
			 "&appreciation=" + encodeURI( form.appreciation.value ) +
			 "&rent=" + encodeURI( form.rent.value ) +
			 "&rent_appreciation=" + encodeURI( form.rent_appreciation.value ) +
			 "&holding=" + encodeURI( form.holding.value );
                xmlhttp.onreadystatechange = state_Change
                xmlhttp.open( "POST", "/cgi-bin/botn.pl", true )
		xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
		xmlhttp.setRequestHeader("Content-length", params.length)
		xmlhttp.setRequestHeader("Connection", "close")
                xmlhttp.send( params )
        } else {
                alert( "Your browser does not support XMLHTTP." )
        }

	return false;
}

function state_Change() {
	// if xmlhttp shows "loaded"
	if ( xmlhttp.readyState == 4 ) {
		if ( xmlhttp.status == 200 ) {
			document.getElementById( id ).innerHTML = xmlhttp.responseText
		} else {
			alert("Problem retrieving XML data")
		}
	}
}