JavaScript Events

A JavaScript function is a section of code that perform a specific task when called. Calling a function is achieved by its name.

Syntax:

function function_name() 
  {
    function code
  }

Example:

<html>
<head>
<script>
function helloFunction()
{
alert("Hello people!");
}
</script>
</head>
<body>
<input type="button" onclick="helloFunction()" value="Press button" />
</body>     
</html>

Result:

JavaScript Event Handlers

Event handling is to drive action following the event, such as onClick, onMouseOver, onKeyUp.
Drive or treating an event brings drive a JavaScript function that will take over the tasks assigned to the event.

Event	Description
onBlur	Action that will be triggered when an element loses focus on.
onChange	Action that will be automatically triggered when changing an item.
onFocus	Action that will be triggered by focusing on an element.
onReset	Action will be initiated when the reset button of a form is pressed.
onSelect	Action that will be triggered when selecting an item.
onSubmit	Action will be initiated when the submit button of a form is pressed.
onClick	Action that will be triggered when you press left click on the mouse.
onDblClick	Action that will be triggered when double click the left mouse button.
onMouseDown	Action that will be triggered when a mouse button is pressed.
onMouseMove	Action that will be triggered when the mouse cursor moves.
onMouseOut	Action that will be triggered when the mouse cursor moves outside item or area bounded.
onMouseOver	Action that will be triggered when the mouse pointer moves over a element or over the surface area.
onMouseUp	Action that will be triggered when the mouse button is released.
onKeyDown	Action that will be triggered when a key is pressed.
onKeyPress	Action that will be triggered when you press and release a key.
onKeyUp	Action that will be triggered when a key is released.
onError	Action that will be triggered after loading an image or failure of a document.
onLoad	Action that will be automatically triggered when loading a document.
onUnLoad	Action that will be automatically triggered when a document doesn’t load.