阿贾克斯同步回调 [英] Ajax synchronous callbacks

问题描述

我有一个pageTest.html在本地文件夹，这个页面调用service.ashx我=？（即返回值参数顺利通过增加+1）与跟随阿贾克斯code：？

I have a pageTest.html in local folder,this page call a service.ashx?i=...(that return value param passed incremented +1) with follow Ajax code:

.
.
getIncr: function(parameters, success){
       $.ajax({
               async: false, 
               type: methodType,
               url: getTarget,
               data: "n="+parameters,
               dataType:"jsonp",
               success: success
             });
    }
.
.

HTML页面调用这个函数的米计时（与脚本..）：

The html page call this function for m time (with script..):

  .    
  var start = function(){
  .
  .
  var val = 0;
  .      
  .
  for(i=0; i<m; i++)
  {
      Foo.getIncr(val, function(returned_n){
          val = returned_n;
      });

  }

};

在阿贾克斯：

在页面加载时，调用假 异步执行中的异步模式，但我的设置。我读到这个问题，并找到了原因，那就是阿贾克斯不能同步从page.html即可调用如果在不同的域service.ashx。 是否有执行的page.html即可同步调用该service.ashx溶液（在不同的域）？

During the page loading, the calls are execute in "Asynchronous mode" but i setting "async: false" in Ajax. I read about this problem and found the reason, that is Ajax can't synch call from page.html to service.ashx if there are in different domain. Is there a solution for execute Synch call in page.html to that service.ashx (in different domain)?

推荐答案

好了，问题是，你不能让同步JSONP请求。它的实现方式是，安迪指出，通过一个所谓的脚本标签黑客。有没有办法jQuery的可以在等待脚本标记要填充停止的JavaScript应用程序的执行。

Well, the problem is that you cannot make synchronous JSONP requests. The way it is implemented is, as Andy pointed out, through a so-called "script tag hack". There is no way jQuery can stop the execution of the javascript application while waiting for a script tag to be filled.

所以，您所呼叫的jQuery的正确的方法做一个JSONP请求，但因为它是JSONP，异步选项不应用，有没有办法解决它。你必须异步处理请求。

So you are calling the right method of jQuery to make a JSONP request but because it is JSONP, the asynchronous option is not applied and there is no way around it. You have to handle the request asynchronously.

在一个侧面说明，它不是使用$就在同步模式的时候是个好主意。如果请求需要太多的时间才能完成，浏览器将停止机会是你的用户会得到一个弹出说的页面不响应。

On a side note, it is not a good idea to use $.ajax in synchronous mode anyway. If the request takes too much time to be completed, the browser will stall and chances are your user will get a popup saying the page is not responding.

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