Absolute positioning in Dynamic HTML

The picture on this page (below) is absolutely positioned (STYLE="position:absolute;"), with an offset of 150 pixels to the right and 250 pixels down from the left-hand corner of the browser screen (its 'parent container'). There's no 'hole' in the page because the picture has been placed completely outside of the page's set of flowing content items, so doesn't have any reserved space in the flowed layout.

Try resizing your browser window - the text (and any other content) will reflow, but the picture will stay exactly where it is in relation to the top left-hand corner of the browser. Remember though that absolute positioning in fact defines an offset from the item's 'parent positioned container'. So if you put an absolutely-positioned item inside a DIV that itself has positioning coordinates (relative or offset) then the item will be placed realtive to the DIV's top left-hand corner.

Last month I abandoned my cross-platform principles and started looking at Microsoft's version of Dynamic HTML, which only works with the Internet Explorer 4.0 browser. The reason was that IE's DHTML is, quite simply, better than NetScape's, particularly for JavaScript programmers looking to add a little client-side trickery to their pages. It's still better this month, so I've carried on looking.

Microsoft's version of DHTML turns every HTML tag in a Web page into a programmable object, which you can access from JavaScript and VBScript routines (Netscape's does something similar, but not as accessible). Until now, tags have been 'static' - the browser processes them as it's loading the page, and after that their details can't be changed. In IE 4, however, the tag can be accessed as an object at any time, allowing you to change its details (now termed 'properties'). This means you can, for example, change the size of the picture created by an <IMG&ldots tag, or the target of an <A HREF&ldots hyperlink. This ability to dynamically alter the properties of HTML tags is the reason it's called Dynamic HTML.