/****

//检查用户名是否存在
function UserNamerefreshMessage(result) {
    document.getElementById("showusernameMessage").innerHTML=result.responseText
}
function startRequest(textbox){
    var url="js/checkusername.aspx";//url地址
    var pars="tbxUserName="+textbox.value;
    var myajax = new ajax(url,pars,UserNamerefreshMessage);
    myajax.post();//也可以时myajax.post();
}

//检查邮箱是否存在
function EmailrefreshMessage(result) {
    document.getElementById("showemialMessage").innerHTML=result.responseText
}
function startCheckEmail(emailbox)
{
    var url="js/checkemail.aspx";//url地址
    var pars="emial="+emailbox.value;
    var myajax = new ajax(url,pars,EmailrefreshMessage);
    myajax.post();//也可以时myajax.post();
}
****/
function ajax(url,pars,fun)
{
    var aj = new Object();
    aj.url=url;
    aj.pars=pars;
    aj.resultHandle=fun;
    aj.createXMLHttpRequest = function() {
        var request = false;
        if(window.XMLHttpRequest) {
            request = new XMLHttpRequest();
            if(request.overrideMimeType) 
            {
                request.overrideMimeType('text/xml');
            }
         }
         else if(window.ActiveXObject) 
         {
            var versions = ['Microsoft.XMLHTTP', 'MSXML.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.7.0', 'Msxml2.XMLHTTP.6.0', 'Msxml2.XMLHTTP.5.0', 'Msxml2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];
            for(var i=0; i<versions.length; i++) 
            {
                try {
                    request = new ActiveXObject(versions[i]);
                    if(request) 
                    {
                        return request;
                    }
                } catch(e) {}
            }
        }
    return request;
    }

    aj.XMLHttpRequest=aj.createXMLHttpRequest();
    aj.processHandle = function()
    {
        if(aj.XMLHttpRequest.readyState==4 && aj.XMLHttpRequest.status == 200) {
            aj.resultHandle(aj.XMLHttpRequest);
        }
    }

    aj.get = function() {
        aj.XMLHttpRequest.onreadystatechange = aj.processHandle;
        aj.XMLHttpRequest.open("GET",aj.url+"?"+aj.pars);
        aj.XMLHttpRequest.send(null);
    }

    aj.post = function() {
        aj.XMLHttpRequest.onreadystatechange = aj.processHandle;
        aj.XMLHttpRequest.open('POST',aj.url,true);
        aj.XMLHttpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        aj.XMLHttpRequest.send(aj.pars);
    }
    return aj;
}