Concept in Definition ABC

Since its founding, it was already seen that the World Wide Web was destined to do great things in the world, something that was palpable with its rapid expansion and adoption in almost all areas.

The convenience of using an online service that does not require the installation of a software in our computer being able to execute it from where we are, it is maximum.

And as if it were a race, web browsers - browsers - began to incorporate functionalities, many times in phase experimental until they were adopted as a standard by the World Wide Web Consortium (W3C) which, at the same time, pushed the development of what could be done from a web page, and the imagination of the developers pulled again and again the potential of the browsers.

The sophistication of the tools led us to the appearance of languages ​​of programming interpreted in the browser Y toolkits to exploit them. This is the case with AJAX.

The name AJAX corresponds to the acronym of Asynchronous JavaScript And XML

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, and consists of a technology that allows running applications on the user's web client (browser), requiring only asynchronous communication with the server.

AJAX is not a technology by itself, it is a package which includes various technologies.

We obviously have the script part, made with an implementation of ECMAScript, generally JavaScript; HTML / XHTML markup languages ​​and CSS style sheets to format the web pages that will be presented to the user and format the data for sending and receiving.

It also includes the necessary mechanisms to connect with the server and exchange data with it (XMLHttpRequest).

All these technologies already existed before 2005, the year in which James Garrett began to refer to them together under the name of AJAX.

AJAX is used when server task can be downloaded to the client, for example by validating in real time the data entered in a form or applying changes to the web page with which the user is interacting if it is not necessary that the change and its consequences be communicated immediately to the server.

By being able to create a web page that replaces the current one, from AJAX you can make it change completely the web page that we are seeing without having to communicate with the server in a immediate.

The security of AJAX lies in that it runs isolated in the browser, and this in turn runs on the operating system.

Before carrying out a harmful action on the system, the code must pass two levels of safety.

This, however, has not prevented the use of the toolkit that conforms AJAX to, for example, execute remote programs that "stick" an advertising page engine to the browser, or that they change their configuration so that it shows a certain home page instead of the one that the Username.

Many times these actions require the user's permission, which applications written to run in the browser can avoid through subterfuge.

These problems have been corrected in the most modern web browsers, which have sophisticated security systems and prevention code execution harmful, allowing them to avoid executing something unwanted.

It is, so to speak, as if the browser "knows" what a JavaScript is going to do before it does, with only its analysis.

The most used web browsers on the market facilitate the use of AJAX on all the software platforms for which they are available (such as Windows, macOS, GNU / Linux, BSD ...).

These include Google Chrome, Mozilla Firefox (and derivatives that use the same rendering engine, which is free software), Microsoft Internet Explorer and Edge, Apple Safari, Opera, and various web browsers for mobile platforms such as iOS or Android.

It should be noted that AJAX is not a standard, although it is based on pieces that are standards.

It can also interact with other technologies, forming a very complete set of tools.

Fotolia photos: Maciek905 / Piotr Adamowicz

Themes in AJAX