//创建对象
function create_obj(){
    var http_request = false;
    //开始初始化XMLHttpRequest对象
    if(window.XMLHttpRequest) { //Mozilla 浏览器
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType) {//设置MiME类别
            http_request.overrideMimeType("text/xml");
        }
    }
    else if (window.ActiveXObject) { // IE浏览器
        try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
        }
    }

    if (!http_request) { // 异常，创建对象实例失败
        return false;
    }

    return http_request;
}

//初始化、指定处理函数、发送请求的函数
//var postStr = "ACT=reply&bookid="+bookid+"&book_content="+ book_content;
//type:post or get
function send_request(http_request,url,postStr) {
    // 确定发送请求的方式和URL以及是否同步执行下段代码
    http_request.open("POST", url, true);
    http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
    http_request.send(postStr);
}





function getCheck(){
    var http_request = create_obj();
    http_request.onreadystatechange = function(){
        if (http_request.readyState == 4) {
            if (http_request.status == 200) {
				var http_result2 = http_request.responseText;
				if('true'==http_result2){
					document.getElementById("chk_username").style.background = strPic2;
				document.getElementById("chk_username").innerHTML = "This username exist now";
				}
else{
				document.getElementById("chk_username").innerHTML = "valid";
}
            }
        }
    }
    var username=document.getElementById('username').value;
    var postStr = "act=check&userid="+ username;
    send_request(http_request,"checkuser.php",postStr);
}



function getCheckEmail(){
    var http_request = create_obj();
    http_request.onreadystatechange = function(){
        if (http_request.readyState == 4) {
            if (http_request.status == 200) {
				var http_result3 = http_request.responseText;
				if('true'==http_result3){
					document.getElementById("chk_Email").style.background = strPic2;
				document.getElementById("chk_Email").innerHTML = "Your email used now,Please change others to try";
				}
else{
				document.getElementById("chk_Email").innerHTML = "valid";
}

            }
        }
    }
    var Email=document.getElementById('Email').value;
    var postStr = "act=check&email="+ Email;
    send_request(http_request,"checkemail.php",postStr);
}