jQuery-修改xmlHttpRequest对象-1.1

function ajax(url, sendData, isAsync, functionList) {
    $.ajax({
        url: url,
        type: "POST",
        async: isAsync,
        data: sendData,
        
        xhr: function(){
            var myXhr = $.ajaxSettings.xhr();
            if(myXhr.upload){ //检查upload属性是否存在
                //myXhr.timeout = 3000;
                myXhr.upload.onprogress = functionList.progressFunction;
            }
            return myXhr; //xhr对象返回给jQuery使用
        },
        
        success: functionList.loadFunction,
        error: functionList.errorFunction
    });
}