DOM

The Document Object Model (DOM) represents an XML or an HTML document as a tree of nodes. Using DOM methods and properties, you can access any element on the page, modify or remove elements, or add new ones. The DOM is a language-independent API (Application Programming Interface) and can be implemented not only in JavaScript, but also in any other language. For example, you can generate pages on the server-side with PHP's DOM implementation (http://php.net/dom).

Take a look at this example HTML page:

<!DOCTYPE html>
<html>
  <head>
    <title>My page</title>
  </head>
  <body>
    <p class="opener">first paragraph</p>
    <p><em>second</em> paragraph</p>
    <p id="closer">final</p>
    <!-- and that's about it -->
  </body>
</html>

Consider the second paragraph (<p><em>second</em> ...

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