Javascript--ajax notes (to be sorted)

JavaScript Ajax

Request.open ("POST", "get.php", true);
Request.setrequestheader ("Content-type", "application/x-www-form-urlencoded");//Tell the server to be a "POST" request
Request.send ("Username= Wang two Dog &password=123456");

HTTP requests have two ways, "post" and "get", "post" is generally used to modify server data when using such as submit form, security, "get" is generally used to request data, the obtained data will be displayed on the URL

var request = new XMLHttpRequest (); Create an asynchronous object, set up an XMLHttpRequest object, IE5, 6 not support, through this object as the foreground and background of the intermediate processor, data interaction

Request.open ("GET", "get.php?") number=1&sex= male ", true);//" GET "defines the way and URL and parameters that are sent after the" post "parameter is written in the send (parameter);
Request.send ();//Send the HTTP request required by the foreground

Request.onreadystatechange = function () {//onreadystatechange Listen for request
if (request.readystate===4&&request.status===200) {//request.readystate Judgment response Change-4 means response complete
Request.status to determine if the request completed--200 complete
var text = Request.responsetext; Get query Results
}
}

Server-side (URL address) need to write the interface to handle the request sent by the client and do the corresponding action

The browser enters the URL in the Address bar and the carriage return belongs to the Get method, the server side receives this HTTP request, in the written script to judge, matches the return page

(The process of returning an HTML page when the browser accesses the server via a URL and the server evaluates to True?) ）

Hit URL in the address bar to send parameters: URL? number=1&sex= Male

When the server returns JSON data, the client uses var jsondate = Json.parse (request.responsetext)//To get the JSON-formatted data object

JQuery Ajax
$ (function () {
$.ajax () {

Type: "POST",//"GET" does not require data
Url:
data:{
Name:$ (). Val (),
Number:$ (). Val (),
Sex:$ (). Val (),
Job:$ (). Val ()
},
DataType: "JSON",
Success:function (obj) {

},
Error:function (obj) {
Alert ("Error occurred:" +obj.status);
}
}

})

Cross-domain

http://www. Abc.com:8080/scripts/jquery.js
Protocol subdomain primary Domain name Port number Request resource address

When the protocol subdomain primary domain port number is not the same, the different domains, the mutual request resources between different domains count as "cross-domain"

Solution:

1, backstage use agent

2, Jsonp
Front DataType: "Jsonp",
JSONP: "Callback",

Background $JSOPN = $
$jsopn.

3, XHR2

Javascript--ajax notes (to be sorted)