Web Front-end development-AJAX entry, web Front-end ajax

Web Front-end development-AJAX entry, web Front-end ajax
What Is AJAX?

AJAX: A New Approach to Web Applications XML

AJAX is a new idea of old technology. We have been familiar with the content it contains before. As follows:

(1) standard-based representation technology using XHTML and CSS

(2) Use DOM for Dynamic Display and Interaction

(3) use XML and XSLT for data exchange and processing

(4) use XMLHttpRequest for asynchronous data retrieval

(5) use Javascript to integrate the above technologies

Just like mixing several wines into cocktails, AJAX gives old technologies new vitality.

Functions of AJAX
(1) Improve the form verification method. You no longer need to open a new page or submit data on the entire page.

(2) You can change the page content without refreshing the page to reduce user waiting time.

(3) obtain data as needed. Only the required data is obtained from the server at a time.

(4) read external data for data processing and integration

(5) asynchronously interacts with the server. During the interaction, the user can continue the operation without waiting.

Compared with traditional Web application models
The AJAX application process is: enter data in the browser-> click the button to submit the request-> the user can continue to do other things; the number of Servlet Processes

Data, concurrent data return-> the browser receives the response-> the current page in the browser shows the response result, which is still ignored due to a short time

But these processes actually exist.

One feature of the traditional Web development thinking model is to submit request information through form, and then turn to a new page to process the request and display the service

Information returned by the server.

See the image below

Ajax disadvantages
(1) AJAX does not have the Back and History functions, that is, it damages the browser mechanism.

(2) AJAX security issues.

(3) weak support for search engines.

(4) The client is too fat, and too much client code causes development costs.

(5) destroying the Exception Handling Mechanism of the program and violating the original intention of URL and resource positioning.

AJAX application scenarios

Summary

Because it can communicate with the server on the page, you do not have to refresh the page as a whole, which reduces the amount of data transmission and increases the response speed of Web applications.

Bring new feelings. It can be considered that AJAX is the set-up of the availability theory of Web standards and Web applications. It greatly improves the availability of Web Applications

The interactive experience with users has finally been widely recognized by users and the market. Therefore, AJAX is the choice of users and the market.