DOM

The Document Object Model, or DOM is an object model used for referencing items on XML or HTML files. The DOM is commonly used when writing Javascript code to access elements of a web page.

Knowing how use the DOM can be essential to understand how to alter values on a existing web page in an easy way.

Examples

Altering an attribute of a HTML Element

Javascript can access elements of a webpage by referring to their ID values. The following line of HTML is for a link that has an id of "url" and points to "http://www.yahoo.com":

<a id="url" href="http://www.yahoo.com">testing</a>

The following Javascript code will find the Element with an id value of url, and will then set the href attribute of it to "http://www.msdn.com"

 // This line fetches and handle to the Element with id ''url'' and returns it to the variable ''link''
 link=document.getElementById('url');
 // This line sets the href attribute of the link item to "http://www.msdn.com"
 link.href="http://www.msdn.com";

External Links

• w3c DOM Specifications
• DOM Tutorials