Clearly, positioning your block of content depends upon the specified STYLE properties. Several documents on Web contain references to the positioning properties available for style sheets -- two worth reviewing are Microsoft's CSS Attributes Reference (under "Positioning Properties") and Netscape's Defining Positioned Blocks of HTML Content.

Employing the various STYLE properties gives you powerful control over the position and look of the blocks of content on your page. Conceptually, then, when we think in DHTML we think of a page as made up of one or more blocks.

Once the blocks have been put into place, you can -- at any time -- change their properties. Position, background, clipping region, z-index -- with the help of JavaScript.