JavaScript Object and Events

The JavaScript Object Hierarchy

Events

The object in a Web pages are organized in a hierarchy. All objects have properties and methods. In addition, some objects also have "events". Events are things that happen, usually user actions, that are associated with an object. The "event handler" is a command that is used tospecify actions in response to an event. Below are some of the most common events :

• onLoad - occurs when a page loads in a browser
• onUnload - occurs just before the user exits a page
• onMouseOver - occurs when you point to an object
• onMOuseOut - occurs when you point away from an object
• onSubmit - occurs when you submit a form
• onClick - occurs when an object is clicked

Events and Object

Event are things that happen, actions, that are associated with an object. Below are some common events and the object the are associated with :

Event	Object
onLoad	Body
onUnload	Body
onMouseOver	Link, Button
onMouseOut	Link, Button
onSubmit	Form
onClick	Button, Checkbox, Submit, Reset, Link

Example : <FORM onSubmit="functionName()">

Image Rollover Example

• With the "window.html" file open, View the Source
• Put the cursor after the line "<A HREF=" and enter :

 <P>
 <A HREF="URL"
 onMOuseOver="document.hot.src='hot1.gif''"
 onMouseOut="document.hot.src='hot2.gif'">
 <IMG name="hot" src="hot2.gif"></A>

• Save the changes and Refresh the Page.

SEE VIDEO

source code : www.youtube.com

Posted in: JavaScript Tutorial