How to implement cross-domain requests with jQuery+JSONP

Today, I would like to share with you how to use jQuery+JSONP to achieve cross-domain request related knowledge, detailed content, clear logic, I believe that most people still know too much about this knowledge, so share this article for your reference, I hope you can learn something after reading this article, let's take a look at it.

   problem: there is a local page demo.html that needs to get data from http://localhost:3561/User/GetAllNames and display it.

   answer: since the two parties in the question are not on the same server, you need to use jsonp for cross-domain access.

  ① client writing

The    client uses the $.getJson method provided in jQuery for cross-domain access. GetJson has three parameters:

     I. url: request address

     II. Data: parameters sent to the server

     III. Callback: callback function if successful

The use of    getJson is basically the same as the ordinary $. Get method, except that getJson needs to add callback=? to the parameters after url This fixed part will be automatically replaced by jQuery. Is the correct function name to execute the callback function. Then the json object returned from a foreign domain is manipulated in the callback function, and the parameter of the callback function callback is the json object.

$.getJSON ("http://localhost:3561/User/GetAllNames?callback=?", function (json) {for (var I = 0; I)

< json.length; i++) { $("#nameList").append("" + json[i] + ""); } }); 　　② 服务端编写   服务端的逻辑主要是将数据序列化为json字符串，然后封装成"callback(json)"的形式，callback为jQuery自动生成并传到服务端的函数名称。下面使用C#实现： public class UserController : Controller{ public string GetAllNames(string callback) { string[] names = new string[] { "张三丰", "张无忌", "令狐冲", "杨过", "郭靖" }; JavaScriptSerializer jss = new JavaScriptSerializer(); string json = jss.Serialize(names); return string.Format("{0}({1})", callback, json); }} 　　至此，便成功解决了问题。

  thinks: if the server has already written callback (e.g. return string.Format ("moty ({0})", json);), how should the client write it?

  reference:

Ajax ("http://localhost:3561/User/GetAllNames", {jsonpCallback:" moty ", dataType:" jsonp ", success: function (json) {for (var I = 0; I < json.length; iTunes +) {$(" # nameList "). Append ("+ json [I] +");}); these are all the contents of the article "how to use jQuery+JSONP to implement cross-domain requests". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.