JavaScript自己封装ajax的js

[javascript]
/**
* 执行基本ajax请求,返回XMLHttpRequest
* Ajax.request({
* url
* async 是否异步 true(默认)
* method 请求方式 POST or GET(默认)
* data 请求参数 (键值对字符串)
* success 请求成功后响应函数，参数为xhr
* error 请求失败后响应函数，参数为xhr
* });
*/     www.zzzyk.com
Ajax = function() {
    function request(opt) {
        function fn() {
        }
        var url = opt.url || "";
        var async = opt.async !== false, method = opt.method || 'GET', data = opt.data
                || null, success = opt.success || fn, error = opt.failure
                || fn;
        method = method.toUpperCase();
        if (method == 'GET' && data) {
            var args = "";
            if(typeof data == 'string'){
                //alert("string")
            args = data;
            }else if(typeof data == 'object'){
                //alert("object")
                var arr = new Array();
                for(var k in data){
                    var v = data[k];
                    arr.push(k + "=" + v);
                }
                args = arr.join("&");
            }
        url += (url.indexOf('?') == -1 ? '?' : '&') + args;
            data = null;
        }
        var xhr = window.XMLHttpRequest ? new XMLHttpRequest()
                : new ActiveXObject('Microsoft.XMLHTTP');
        xhr.onreadystatechange = function() {
            _onStateChange(xhr, success, error);
        };
        xhr.open(method, url, async);
        if (method == 'POST') {
            xhr.setRequestHeader('Content-type',
                    'application/x-www-form-urlencoded;');
        }
        xhr.send(data);
        return xhr;
    }
    function _onStateChange(xhr, success, failure) {
        if (xhr.readyState == 4) {
            var s = xhr.status;
            if (s >= 200 && s < 300) {
                success(xhr);
            } else {
                failure(xhr);
            }
        } else {
        }
    }
    return {
        request : request
    };
}();

[javascript]
Ajax.request({
    url : path + "/report/topn/topn_data.jsp",
    data : {
        datatype : datatype
    },
    success : function(xhr) {
        onData(xhr.responseText);
    },
    error : function(xhr) {

    }
});

补充：web前端 , JavaScript ,