Introduction to Web front-end development--ajax

What is Ajax

Ajax:a New approach to WEB applications XML

Ajax is a new idea of old technology.

It includes everything we've been exposed to before. For example, the following:

(1) Standard-based presentation technology using XHTML and CSS

(2) dynamic display and interaction using the DOM

(3) data exchange and processing using XML and XSLT

(4) using XMLHttpRequest for asynchronous data retrieval

(5) using JavaScript to fuse the above technologies together

Like mixing several kinds of wine into cocktails, Ajax lets old technology make new life.

the role of Ajax
(1) Improve the form verification method, no longer need to open a new page. And no longer need to submit the entire page data

(2) You can change the content of the page without having to refresh the page. Reduce user wait Time

(3) Obtain data on demand, each time only from the server side to obtain the required data

(4) Read the external data, the integration of data processing

(5) Asynchronously interacts with the server, and the user does not have to wait during the interaction. can still continue operation

the process of AJAX application patterns compared to traditional Web application patterns
The process for AJAX applications is to enter data in the browser, click the button submit request, and the user can continue to do other things; the servlet is processing the number

The browser receives a response to the current page in the browser, and the response results are displayed. There are still some processes in this, because time is too short for you to overlook

The place where it was. But in fact, these processes are present.

One of the characteristics of traditional Web development thinking mode is to submit request information through form form, then turn to a new page processing request and display the service

Information returned by the device side.

The following view picture

Ajax Disadvantages
(1) Ajax does not have back and history functions, that is, the destruction of the browser mechanism

(2) Ajax security issues.

(3) The search engine support is weaker.

(4) The client is too fat, too many client code causes the development cost.

(5) The exception handling mechanism of destroying program, violating the original intention of URL and resource location.

Ajax Application Scenarios

Summary

Because you can communicate with the server within the page, you do not have to refresh the page overall, reducing the amount of data transferred. Improves the responsiveness of Web applications, giving users

Bring a whole new feeling.

The ability to think of Ajax as the culmination of usability theories for web standards and Web applications. It greatly improves the usability of Web applications

And the user's interactive experience. Finally has been widely recognized by users and the market. So it can be said that Ajax is the user and market choice.

Introduction to Web front-end development--ajax