Jquery ajax执行顺序 返回自定义错误信息

1.多个Ajax 在一个function中的执行顺序

   由于Jquery中的Ajax的async默认是true(异步请求),如果想一个Ajax执行完后再执行另一个Ajax, 需要把async=false就可以了.

代码

function  TestAjax(){
             var  UserName  =  $( " #txtUserName " ).val();
            $.ajax(
            {
                url:  " AjaxCheckUserName.htm " ,
                async:  false ,
                success:  function  (data) {
                    alert(data);
                }
            });
            alert( ' Test ' );
            $.ajax({
                url:  " AjaxHandler.ashx " ,
                async:  false ,
                data:  " UserName= "   +  UserName,
                success:  function  (data) {
                    $( " #divAjax " ).html(data);
                },
                error:  function  (msg) {
                    alert(msg.responseText);
                }
            });
        }

2. 返回自定义错误

设置 StatusCode = 500,

触发Ajax的错误(error), 在接收到数据显示自定义信息

error: function (msg) {
                    alert(msg.responseText);
                } 

 

 context.Response.StatusCode = 500;
 context.Response.Write("请输入用户名");

代码

string  sUserName  =  context.Request.QueryString[ " UserName " ];
             if  ( ! string .IsNullOrEmpty(sUserName))
            {
                context.Response.Write( string .Format( " Hello {0}! " , sUserName));
            }
             else
            {
                context.Response.StatusCode  =   500 ;
                context.Response.Write( " 请输入用户名 " );
            }

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转载于:https://www.cnblogs.com/chinabc/archive/2010/11/30/1892452.html