DOM: Add/Remove Event Handler

By Xah Lee. Date: . Last updated: .

This page shows you how to add/remove event handler.

Here's a simple mouse over event.

click me

Here's the HTML code:

<div id="e83301">click me</div>

Here's the JavaScript code:

const ff = ((e) => { e.target.innerHTML = "yes"});

const ele = document .getElementById("e83301");

ele.addEventListener("click", ff);

This is a simple example of a Event. The event is "click". When user clicks, the browser fires the event, then calls the function attached to that event. (function for this purpose is called the “event handler”.)

addEventListener

node.addEventListener(event_name, function_name)

Adds a event handler.

event_name is a string representing a event.

function_name is a function that will be called when the event happens.

The event handler function function_name is passed a event object as argument.

The element that fired the event can be accessed by the property key "target". That is, event_object.target.

[see JS: What's “this” in a event handler?]

removeEventListener

node.removeEventListener(event_name, function_name)

List of Event Names

https://developer.mozilla.org/en-US/docs/Web/Events

https://www.w3.org/TR/DOM-Level-3-Events/

DOM How-To

  1. DOM: Basic DOM Methods
  2. Get Elements by ID, Tag, Name, Class, CSS Selector
  3. Change CSS
  4. Change Node Content
  5. Create/Insert Node
  6. Remove Node
  7. Get Element's Attribute Value
  8. Set Element's Attribute Value
  9. Remove Element's Attribute Value
  10. List/Add/Remove Class Attribute
  11. Add/Remove Event Handler
  12. DOM: Navigate DOM Tree
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