JavaScript jquery and Ajax summary _javascript tips

In fact, before learning, it has been used js,jquery and Ajax, but at that time did not know the difference, all as JS look, and then others said Jquery,ajax feel like very advanced, wait until their own study time, but for these clearer a little, Here's how to write my summary.

Brief introduction

Javascript

JavaScript, a literal-translation scripting language, is a dynamically typed, prototype based language with built-in support classes. Its interpreter is called the JavaScript engine, a part of the browser, widely used in the scripting language of the client, and was first used on HTML pages to add dynamic functionality to HTML pages. But now JavaScript can also be used for Web servers, such as Node.js.

In 1995, Netscape's Brandon Aick was first designed and implemented in the Netscape Navigator browser. Because Netscape and the company's marketing cooperation, and Netscape Management wants it to look like Java, so named JavaScript. But in fact its semantics are closer to self and scheme.

To gain technical advantage, Microsoft has introduced JScript, which can also be run on browsers with JavaScript. In 1997, in coordination with ECMA (European Computer Manufacturers Association), a working group composed of Netscape, Sun, Microsoft and Borland established a unified standard: ECMA-262. Because JavaScript is compatible with the ECMA standard, it is also known as ECMAScript.

Juery

jquery is a cross-browser JavaScript library that simplifies the operation between HTML and JavaScript. The first version was released by John Ressig (John resig) on the BarCamp NYC in January 2006. It is currently being developed by the development team led by Dave Methvin. Of the world's top 10,000 most visited sites, 65% use jquery, the most popular JavaScript library of all time.

Ajax

Ajax, the "Asynchronous JavaScript and XML" (Asynchronous JavaScript and XML technology), refers to a set of browser-side web-page development techniques that integrate a number of technologies. The concept of Ajax is presented by Jessi James Jarrett [1].

Traditional Web applications allow the user to fill out a form (form) and send a request to the Web server when the form is submitted. The server receives and processes the form and sends it back to a new Web page, but it wastes a lot of bandwidth because most of the HTML code in the previous two pages is often the same. Due to the need to send a request to the server for each application, the response time of the application depends on the server's response time. This causes the user interface to respond much more slowly than the native application.

In contrast, AJAX applications can send and retrieve only the necessary data to the server and use JavaScript on the client to handle the response from the server. The server responds faster because the amount of data exchanged between the server and the browser is substantially reduced (about 5% of the original) [source request]. At the same time, a lot of processing work can be done on the requesting client machine, so the load on the Web server is reduced.

Like DHTML or Lamp,ajax is not a single technology, but an organic use of a range of related technologies. Although its name contains XML, the actual data format can be replaced by JSON, further reducing the amount of data to form the so-called Ajaj. The client and the server do not need to be asynchronous either. Some Ajax-based "derivation/Synthesis" (derivative/composite) technologies are also emerging, such as Aflax.

Difference

As we can see from the introduction, JavaScript is a scripting language, and jquery is the encapsulation of JS, Ajax is a mixture of many technologies, their differences are obvious, but they are all for our program provides a more convenient technology.

Summarize

Javascript

Jquery+ajax

Many times in fact, directly watching the video effect is not good, often into a this is what the situation, this time, more to knock some code simple error effect is relatively good, the beginning will certainly follow the knock, knock more slowly know how to use, of course, after the practice, but also need to go back to the theory to learn ~

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