Asp.net 应用之 ajax的应用

封装的很ＮＢ的ajax函数，羡慕中．．．．．
１．判断浏览器支持操作xml操作类型
function bg_Ajax_GetXMLHttpRequest() {
    if (window.XMLHttpRequest) {
        return new XMLHttpRequest();
    } else {
        if (window.Ajax_XMLHttpRequestProgID) {
            return new ActiveXObject(window.Ajax_XMLHttpRequestProgID);
        } else {
            var progIDs = ["Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"];
            for (var i = 0; i < progIDs.length; ++i) {
                var progID = progIDs[i];
                try {
                 var x = new ActiveXObject(progID);
                 window.Ajax_XMLHttpRequestProgID = progID;
                 return x;
                } catch (e) {
                }
            }
        }
    }
    return null;
}
２．回调函数
function bg_Ajax_Callback(url, postData, callback)
{
    var x = bg_Ajax_GetXMLHttpRequest();
    var result = null;
    if (!x) {
        result = { "value":null, "error": "NOXMLHTTP"};
        if (debugErrors) {
            alert("error: " + result.error);
        }
        if (clientCallBack) {
            clientCallBack(result);
        }
        return result;
    }

    x.open("POST", url, callback ? true : false);
 x.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=utf-8");
    if (callback) {
        x.onreadystatechange = function() {
            var result = null;
            if (x.readyState != 4) {
                return;
            }
            callback(x.responseText)
        }
    }
    x.send(postData);
}