THE WORLD'S LARGEST WEB DEVELOPER SITE
HTML CSS JAVASCRIPT SQL PYTHON PHP BOOTSTRAP HOW TO W3.CSS JQUERY XML MORE FORUM EXERCISES REFERENCES

JS Tutorial

JS HOME JS Introduction JS Where To JS Output JS Statements JS Syntax JS Comments JS Variables JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Events JS Strings JS String Methods JS Numbers JS Number Methods JS Arrays JS Array Methods JS Array Sort JS Array Iteration JS Dates JS Date Formats JS Date Get Methods JS Date Set Methods JS Math JS Random JS Booleans JS Comparisons JS Conditions JS Switch JS Loop For JS Loop While JS Break JS Type Conversion JS Bitwise JS RegExp JS Errors JS Scope JS Hoisting JS Strict Mode JS this Keyword JS Let JS Const JS Arrow Function JS Classes JS Debugging JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words JS Versions JS Version ES5 JS Version ES6 JS JSON

JS Forms

JS Forms Forms API

JS Objects

Object Definitions Object Properties Object Methods Object Accessors Object Constructors Object Prototypes Object ECMAScript 5

JS Functions

Function Definitions Function Parameters Function Invocation Function Call Function Apply Function Closures

JS HTML DOM

DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM CSS DOM Animations DOM Events DOM Event Listener DOM Navigation DOM Nodes DOM Collections DOM Node Lists

JS Browser BOM

JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies

JS AJAX

AJAX Intro AJAX XMLHttp AJAX Request AJAX Response AJAX XML File AJAX PHP AJAX ASP AJAX Database AJAX Applications AJAX Examples

JS JSON

JSON Intro JSON Syntax JSON vs XML JSON Data Types JSON Parse JSON Stringify JSON Objects JSON Arrays JSON PHP JSON HTML JSON JSONP

JS vs jQuery

jQuery Selectors jQuery HTML jQuery CSS jQuery DOM

JS Examples

JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Exercises JS Quiz JS Certificate

JS References

JavaScript Objects HTML DOM Objects


JavaScript Events

❮ Previous Next ❯

HTML events are "things" that happen to HTML elements.

When JavaScript is used in HTML pages, JavaScript can "react" on these events.

HTML Events

An HTML event can be something the browser does, or something a user does.

Here are some examples of HTML events:

  • An HTML web page has finished loading
  • An HTML input field was changed
  • An HTML button was clicked

Often, when events happen, you may want to do something.

JavaScript lets you execute code when events are detected.

HTML allows event handler attributes, with JavaScript code, to be added to HTML elements.

With single quotes:

<element event='some JavaScript'>

With double quotes:

<element event="some JavaScript">

In the following example, an onclick attribute (with code), is added to a <button> element:

Example

<button onclick="document.getElementById('demo').innerHTML = Date()">The time is?</button>
Try it Yourself »

In the example above, the JavaScript code changes the content of the element with id="demo".

In the next example, the code changes the content of its own element (using this.innerHTML):

Example

<button onclick="this.innerHTML = Date()">The time is?</button>
Try it Yourself »

JavaScript code is often several lines long. It is more common to see event attributes calling functions:

Example

<button onclick="displayDate()">The time is?</button>
Try it Yourself »

Common HTML Events

Here is a list of some common HTML events:

Event Description
onchange An HTML element has been changed
onclick The user clicks an HTML element
onmouseover The user moves the mouse over an HTML element
onmouseout The user moves the mouse away from an HTML element
onkeydown The user pushes a keyboard key
onload The browser has finished loading the page

The list is much longer: W3Schools JavaScript Reference HTML DOM Events.

What can JavaScript Do?

Event handlers can be used to handle, and verify, user input, user actions, and browser actions:

  • Things that should be done every time a page loads
  • Things that should be done when the page is closed
  • Action that should be performed when a user clicks a button
  • Content that should be verified when a user inputs data
  • And more ...

Many different methods can be used to let JavaScript work with events:

  • HTML event attributes can execute JavaScript code directly
  • HTML event attributes can call JavaScript functions
  • You can assign your own event handler functions to HTML elements
  • You can prevent events from being sent or being handled
  • And more ...

You will learn a lot more about events and event handlers in the HTML DOM chapters.

Test Yourself With Exercises

Exercise:

The <button> element should do something when someone clicks on it. Try to fix it!

<button ="alert('Hello')">Click me.</button>

Start the Exercise

❮ Previous Next ❯