THE DOM

Javascript is part of your web browser. Some older browsers and some free modern ones do not always have Javascript built into them. Netscape 3+ and Internet Explorer 3+ do.
The DOM (Document Object Modle) is your web page and how Javascript can interact with items within the page. For example you may create a FORM in your web page which contains some text boxes and buttons. Javascript can be used to manipulate the form's elements and attributes, such as displaying text into a text box after a calculation has been made without reloading the page or presenting a new page to the user.
The DOM also allows you to move objects around the page such as images or text, and hide them like menus. An object is anything inside your web page that the scripting language provides methods and information on, such as the Form, or Image.

The rest of this Reference guide gives you the syntax and the majority of functions in Javascript.