// global flag
var isIE = false;

var req;


//Call server with url
function loadXMLDoc(url) {
    // branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = processReqChange;
        req.open("GET", url, true);
        req.send(null);
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = processReqChange;
            req.open("GET", url, true);
            req.send();
        }
    }
}

//Process response
function processReqChange() {
    // only if req shows "loaded"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            handleResult();
        } else {
            alert("There was a problem retrieving the XML data:\n" +
                req.statusText);
        }
    }
}


// Set result text
function handleResult() {
	
	//Get item node from xml result.
    var items = req.responseXML.getElementsByTagName("item");

    // Get target span element
	oResult = document.getElementById("result");
	if(items.length > 0)
	{
		//Set result text
		oResult.innerHTML = items[0].firstChild.data;
		
		faderesult();
		
		//Check if alert chould be displayed
		if(document.getElementById("dispalert"))
		{
			if(document.getElementById("dispalert").checked)
			{
				alert("The result is " + items[0].firstChild.data);
			}
		}
	}
}


//Click event handler for add button
function addclick()
{
	//get values
	val1 = document.getElementById("val1").value;
	val2 = document.getElementById("val2").value;
	
	//call server
	loadXMLDoc("calc.php?no1=" + val1 + "&no2=" + val2);
}

//Colors to use when fading the result area
var Color= new Array();
Color[7] = "e1e1e1";
Color[6] = "e0e0e0";
Color[5] = "ffffdd";
Color[4] = "ffffcc";
Color[3] = "ffffbb";
Color[2] = "ffffaa";
Color[1] = "ffff99";

function faderesult()
{
	if (document.getElementById('fade')) {
		
    	for(iCounter=1;iCounter < 8; iCounter++)
		{
			setTimeout("setbg('#" + Color[iCounter] + "')", iCounter * 150);
		}
		
		setTimeout("setbg('transparent')", 8 * 150);
	}
}

function setbg(col)
{
	oResult = document.getElementById('fade');
	oResult.style.backgroundColor = col;
}