Get a 2018/04/23 of Ajax basics

1. What is Ajax?

The main purpose is to implement asynchronous communication between client and server, and to implement local refresh of the page.

2. Synchronous and Asynchronous!

Synchronization: When multiple threads send a request to a data at the same time, it must be a first execution to give B, there will be a blocking situation, but is thread-safe, to avoid deadlock

Async: When multiple threads want a data sending request at the same time, the resource is given a, but B can also be accessed, so that the efficiency is higher than the synchronization

3.Ajax Execution Process

1). Create a Xmlhttprequets

2). Create a new HTTP request, and specify the request method, already URL

3). Set a function to respond to requests for HTTP request status

4). Send Request

5). Gets the data returned by the asynchronous call

6). Local refresh via JavaScript and Dom

Case, through a native Ajax understanding (4/23 complement)

Get a 2018/04/23 of Ajax basics