var xmlHttp;
var elm;

function createXmlHttp()
{
	if(window.ActiveXObject)
	{
		xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
	}
	else if(window.XMLHttpRequest)
	{
		xmlHttp = new XMLHttpRequest();
	}
}

function callService(srvc,elmnt)
{
	createXmlHttp();
	
	elm = elmnt;
	service = srvc;
	
	if(document.getElementById('fromValue').value=="")
	{
		alert("Please input correct amount");
		
		return;
	}
	
	var url = "ajax/service.php";
	var query = "service="+srvc;
	
	if(srvc == "convert")
	{
		query += "&fromCurrency=" + document.getElementById('fromCurrency').value + 
				"&toCurrency=" + document.getElementById('toCurrency').value + 
				"&fromValue=" + document.getElementById('fromValue').value; 
	}
	
	xmlHttp.open("POST",url,true);
	xmlHttp.onreadystatechange = processServiceData;
	xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	xmlHttp.send(query);
	
}

function processServiceData()
{
	if(xmlHttp.readyState == 4)
	{
		if(xmlHttp.status == 200)
		{
			serverReturn = xmlHttp.responseText;
			
			//alert(serverReturn);
			
			document.getElementById(elm).innerHTML = serverReturn;
		}
	}
}