Chapter 13. The Document Object Model

When you open a web page in your browser, the browser retrieves the page’s HTML text and parses it, much like the way our parser from Chapter 11 parsed programs. The browser builds up a model of the document’s structure and then uses this model to draw the page on the screen.

This representation of the document is one of the toys that a JavaScript program has available in its sandbox. You can read from the model and also change it. It acts as a live data structure: when it is modified, the page on the screen updates to reflect the changes.

Document Structure

You can imagine an HTML document as a nested set of boxes. Tags such as <body> and </body> enclose other tags, which in turn contain other tags or text. ...

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