JavaScript Events

HTML Events

An HTML event can be something the browser does, or something a user does. For example, button click, input field changed, page loading finished, etc.

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.

Common HTML Events

Below is a list of some common HTML events:

• 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

JavaScript Event Handlers

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

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