Basic Ajax knowledge points (learning notes)

It has been a long time since Ajax came out, and many Ajax frameworks for rapid development of Ajax websites have also been used for many times in the project, but none of them have been systematically summarized. Here we will sort out the relevant knowledge points, which will not only facilitate learning, but also facilitate future searches in the project. (This article does not involve Ajax implementation details)

I. What is Ajax?

Ajax (Asynchronous JavaScript and XML), or Ajax, is a group of interrelated web development techniques used for creating interactive (interactive) web application of rich Internet applications (rich Internet applications ).

Ii. Advantages (Advantages)

1. Fewer requests

2. Smaller bandwidth

3. Reduce loading time

4. Stronger interaction

5. faster response

6. Do not refresh

Iii. disadvantages (disadvantages)

1. An Ajax request often has no browser browsing history.

2. It disables Web Page Status bookmarks.

3. It is difficult for search engines to capture Ajax content.

4. Ajax requests cannot span Domains

5. Ajax is not easy to test.

Iv. Ajax Security

1. Ajax does not introduce new security vulnerabilities in Web applications. (JavaScript + XML ).

2. Therefore, we still need client-side checking for web applications and reduce server attacks.

Note:

SQL injections,

Javascript injections.

Data validation,

Business logic on the server,

Do not assume every request is real.

5. Use of AJAX

1. XMLHttpRequest (important object)

2. remoting Scripting (IFRAME Technology)

6. Ajax framework

1.asp.net Ajax technology

2. jquery framework
Jquery is a fast and concise JavaScript library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

Powerful functions: jquery core, selectors, attributes, traversing, manipulation, CSS, events, Ajax, utilities, jquery UI, and Plugins.

For more information, see jquery Syntax: http://docs.jquery.com/

3. ajaxrequest

Ajaxrequest is a lightweight Ajax application.ProgramThe development framework is compatible with Firefox, ie, opera, and Safari, allowing you to easily perform operations that are frequently used in Ajax, thus simplifying development steps and reducing duplication.CodeWrite volume.

Jaxrequest supports multiple concurrent requests. Therefore, you can use only one ajaxrequest object on a page, or use one ajaxreqest for the same type of operations to reduce code writing.

For usage see http://www.xujiwei.cn/works/ajaxrequest/, here you can download ajaxrequest framework

4. Similar to the lightweight ajaxrequest framework, extracted from the project

Object-based JavaScript allows you to send and retrieve data from a refreshing page. Ajax. js

5. There are alsoPrototype, extjs, Yahoo, YuiAnd many other JavaScript frameworks that contain Ajax. (Ajax requests are essentially oo encapsulation of XMLHttpRequest objects)

 

 

Best regards,

Charles Chen

MSN: gotosunny@msn.com