并发Ajax调用 [英] concurrent ajax calls

问题描述

我想jQuery的同时ajax调用做，但我还没有找到关于它的任何特殊。当我做2 Ajax调用，正在启动另外一个第一个完成之后。我试过 $ ajaxSetUp {（异步：真）} ，但它没有工作，我想要的方式。谁能帮我这个？

I am trying to do concurrent ajax calls in jquery but I haven't found anything specific regarding it. When I make 2 ajax calls, another one is being started only after the first one is finished. I tried $.ajaxSetUp{(async: true)}, but it didn't work the way i wanted. Can anyone help me with this?

我有一个表格和表格提交我用 form.js 的ajaxSubtmit我的格式有文件输入和

I have a form and on form submit I use the ajaxSubtmit of form.js as my form has file input as well.

$("form").submit(function() {
  $(this).ajaxSubmit();
  $.getScript("url");
  return false; // to stop the normal working of form submit and submit form by ajax
})

这里的第二个AJAX被称为第一个完成后才能使用。

here the second ajax is called only after the first one is finished.

推荐答案

这就是你说的所谓竞争状态。 为了避免它，你有两个选择，要么你创建一个数组来存储每个请求，或创建用于存储每个请求的局部变量。 这里有一个简单的例子，避免竞争条件：

So that's what you said is called race condition. To avoid it you have two options, either you create an array to store each request, or you create a local variable to store each request. Here's a simple example that avoids the race condition:

function customCallBack()
  {//    Ajax Status finished       http status OK
    if( (this.readyState == 4) && (this.status == 200) )
     {
       alert(this.responseText);
     }
  }

function anotherCallBack()
  {//    Ajax Status finished       http status OK
    if( (this.readyState == 4) && (this.status == 200) )
      {
        console.log(this.responseText);
      }
  }


function asyncPost(url, postArray, functionCallBack)
  {
    var request, query; //request must be a local var to avoid race condition
    query = '';
    for (i in postArray)//format post params
      {
        query += i + '=' + postArray[i] + '&';
      }
    try
      {//for modern browsers
        request = new XMLHttpRequest;
      }
    catch (err)
      {// legacy IE
        request = new ActiveXObject("Microsoft.XMLHTTP");
      }
       // your custom call back function
    request.onreadystatechange = functionCallBack;
    //            type   url  true for async call, false for sync call
    request.open("POST", url, true);

    //Header sent to indicate a post form
    request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

    //making a post call
    request.send(query);
  };

//calling

asyncPost('yourUrl', {'field1' : 'value1', 'field2': 10}, customCallBack);

var post = new Array();
post['field1'] = 'value1';
post['field2'] = 10
//calling againg
asyncPost('anotherUrl', post, anotherCallBack);


// In jquery is like above, because you need the ajax call in a custom function
// and create a local var to hold your call:
function jqAjax(url)
  {
    var mycall  = $.get(url);
  }

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