HTML is a continually evolving language. The primary purpose of this document has been to provide a reasonable subset of the language that permits the creation of HTML documents that will look reasonable on most Web browsers.
This section covers several "advanced", proposed aspects of HTML known to work on Netscape browsers. Browsers that do not support these features will usually just ignore them.
The ALIGN option first appeared in <IMG> and only supported TOP, CENTER, and BOTTOM. Now, the ALIGN option can appear within many HTML elements and LEFT and RIGHT justify settings have been added. One problem with a LEFT or RIGHT justified image is that additional HTML elements behave as if the display window has temporarily narrowed while flowing around the image. If one wishes to "jump" just past the bottom of the image before the next HTML action starts, a special <BR CLEAR=. . .> element with CLEAR set to LEFT or RIGHT must be inserted to terminate the special alignment.
There are several proposed HTML extensions for performing page centering of text and images (with sample output to show if your browser understands):
This is a test of center alignment of words and images
within a paragraph.
The quick brown fox jumped over the lazy dog.
A document page can have a background pattern or color by specifying an image file or color code within the <BODY> element. Image files will be automatically "tiled" to fill the window.
<BODY BACKGROUND="image.gif">
<BODY BGCOLOR="#ffffee">
Comments can be placed in a document by using the HTML comment element.
<!-- This is a comment -->
It is best to keep comment elements entirely on one line; some browsers have problems with comments that span multiple lines.