Introduction to AJAX

AJAX is a technology that can update parts of a web page without reloading the entire web page.

1. What is ajax:
(1). Ajax is asynchronous JavaScript and XML, and the entire English process is Asynchronous JavaScript and XML.
(2).ajax can realize asynchronous updates of local web pages by exchanging a small amount of data with the background, avoiding the need to refresh the page.
Under normal circumstances, if you want to update the data of a web page, you need to refresh the entire page. If you use ajax, you can only refresh partially.

AJAX working principle

2. AJAX is based on the existing Internet standards:
ajax is not new technology, but based on existing Internet standards and technologies:
(1).XMLHttpRequest object (asynchronous exchange of data with the server).
(2).JavaScript/DOM (information display/interaction).
(3).CSS (define styles for data).
(4).XML (as the format for conversion data).
3. Code example:
The above has given a basic introduction to ajax. Here is a simple code example. Let’s feel its function first:

       
  
原来的内容
 查看效果  

The path of demo/ajax/txt/demo.txt in the code can be changed to create it locally and observe the effect.