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Understand What Is AJAX and How to Use It in Your Code

Reading time 2 min
Published Aug 8, 2017
Updated Jan 21, 2020

Without AJAX, our web browsers would constantly be reloading. AJAX allows performing various processes and updates without reloading websites.

What is AJAX, and what does it stand for? It's an abbreviation of Asynchronous Javascript and XML. Asynchronous refers to a bunch of events that happen in irregular time intervals.

What Is AJAX: Main Tips

  • By combining JavaScript, CSS, and XML, AJAX allows reloading only specific elements of the page instead of the entire page.
  • AJAX is applied to create fast, dynamic, and modern websites, such as Google, Facebook, YouTube or Twitter.
  • AJAX is not dependent on what browser it's running on.

AJAX: Standards and Principles

Since AJAX is a technology widely used in modern interactive websites, it has to follow all the modern Internet standards as well. Let's break down its main principles to learn AJAX better:

  • For the asynchronous data exchange with the server, it creates and sends an XMLHttpRequest object for the server to process.
  • DOM and JavaScript are needed for making the website interactive.
  • CSS is used for data styling.
  • As the name of AJAX tells us, the format chosen to transfer the data formatting is XML.

AJAX Explained: Step by Step

To better learn how to use AJAX, let's view a short AJAX tutorial on how the system works:

  1. As an event happens (say, you receive an email), the browser creates a XMLHttpRequest object and sends the request to the server.
  2. After processing the request, the server responds and returns data to the browser.
  3. Then, the browser receives the data, processes it and displays to the user (they see an email notification on their screens).

What Is AJAX: Summary

  • AJAX combines elements of JavaScript, CSS, and XML.
  • It saves us time because instead of the whole page, only certain parts of it are reloaded.
  • AJAX runs on any browser, so a lot of popular websites use it in their programming.
What Is JavaScript Used For?
Tutorial
Introduction
Output
Syntax
Comment
Commands
Operators
Comparison and Logical Operators
Data Types
Math.random()
Type Conversion
Function Definitions
Events
Objects
Object Properties
Prototype
Array
Sorting Arrays
Strings
Numbers
Number Format
Math Object
Onclick Event
Date
Date Formats
Scope
Regular Expressions
Reserved Words
Common Mistakes
Performance
Forms
Form Validation
Window: The Browser Object Model
Popup Boxes
Cookies
JSON
AJAX Introduction
AJAX Form
Automatic File Download
Functions
Array Methods
String Methods
Date Methods
Timing Events
Cheat Sheet
JavaScript in HTML
HTML DOM Methods
HTML DOM Changing HTML
HTML DOM Animation
HTML DOM EventListener
HTML DOM Navigation
HTML DOM NodeList
HTML DOM Element Nodes
Array Functions
Boolean
Calling a Function
Date Functions
Global Objects
Input Text
Operator
Statements
String Functions
Math
Math.random
Number
RegEx
alert
array.filter
array.length
array.map
array.reduce
array.push
array.sort
break and continue
className
confirm
decodeURIComponent
for
forEach
if
indexOf
innerHTML
location.reload
number.toString
onclick
onload
parseInt
prompt
replace
setAttribute
setInterval
setTimeout
slice
splice
string.includes
string.indexOf
string.split
style.display
submit
substr
substring
switch
test
throw, try and catch
toLowerCase
toUpperCase
use strict
while
window.history
window.location
window.navigator
window.screen