How to use jquery to implement ajax asynchronous request to return json data code details

Jquery's asynchronous ajax request receiving and returning json data method is simple to set up. One is that the server handler returns json data, and the other is that the datatype of the ajax sending setting is set to jsonp format data or json format.

The code example is as follows:

$('#send').click(function () {
    $.ajax({
        type : "GET",
        url : "a.php",
        dataType : "jsonp",
        success : function (data) {
            $.each(data.items, function (i, item) {
                $("<img class=&#39;para&#39;/> ").attr("src", item.media.m).appendTo("#resText");
                if (i == 3) {
                    return false;
                }
            });
        }
    });
});

$.ajax method is as follows:

$.ajax({ 
   type: "POST",
   url:  ctxRoot+'FolderAction!saveInformSetting.action',
   data: 'jsonStr=' + inform_settingListStr,
   dataType: "json",
   complete: function(data){
       //在这里做些事情，假设返回的json数据里有name这个属性
       //有时候可以直接data.name或者data['name']去访问
       //但有时候，却要通过var jsonData = eval("("+data.responseText+")");才可以通过jsonData.name访问，而且这种情况下，需要是complete而不是success
   }
   });
$.ajax(options)

This is the most basic JQuery Ajax method, with only one parameter options, which contains Request information and callback function information. Parameter contents are all in the form of key:value pairs, and they are all optional.

The syntax is as follows:

$.ajax({options});
url: (string) The address to send the request, which can be a server page or a WebService action.
type: (string) Request method, POST or GET
data: (object) Data brought when sending a request to the server. It is in the form of key:value pair, such as: {name:"grayworm",sex:"male"}, if it is an array {works:["work1","work2"]}
dataType: (string) expected return type of data. xml, html, json, text, etc.
beforeSend: (Function) is triggered before sending an ajax request. If false is returned, the request will be canceled. If the asynchronous request needs to display gif animation, the visibility of the corresponding should be set here.

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