var xhr;

function getXHR()
{
	try {
		xhr=new ActiveXObject("Msxml2.XMLHTTP");
	} catch (e) {
		try {
			xhr=new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e) {
			xhr=false;
		}
	}
	if(!xhr&&typeof XMLHttpRequest!='undefined')
	{
		xhr=new XMLHttpRequest();
	}
	return xhr;
}


function openXHR(method,url,callback)
{
	getXHR();
	xhr.open(method,url);
	xhr.onreadystatechange=function()
	{
		if(xhr.readyState!=4)return;
		callback(xhr);
	}
	xhr.send(null);
}

function loadXML(method,url,callback)
{
	getXHR();
	xhr.open(method,url);
	xhr.setRequestHeader("Content-Type","text/xml");
	xhr.setRequestHeader("Content-Type","utf-8");
	xhr.onreadystatechange=function()
	{
		if(xhr.readyState!=4)return;
		callback(xhr);
	}
	xhr.send(null);
}

function addFavorite(targetId, addType)
{
	loadXML("get","favorite_check.aspx?id=" + targetId +"&type=" + addType, writeResut);
}

function writeResut(xmlDom) 
{
	var result	= xmlDom.responseXML.getElementsByTagName("addFavorite")[0].getAttribute("result");

	if(result == "true")
	{
		alert("收藏任务成功！");
		return false;
	}
	else if (result == "exist")
	{
		alert("您已经收藏过了！");
		return false;
	}
	else if (result == "illegal")
	{
		alert("收藏操作非法！");
		return false;
	}
	else if (result == "nologin")
	{
		alert("请先登陆后操作！");
		return false;
	}
	else
	{
		alert("其它错误！");
		return false;
	}
}