W3C XHTML Validation

It's strange to admit that I'm not sure what pushed me in this direction. I've always avoided trying for validation before as my HTML, like everyone elses, contains multiple hacks for cross-browser, cross-platform compatibility.

Naturally I have tried to keep the website user-interface from changing during this process but the following changes have resulted from this effort:

• Rounded corners of the content boxes are lost - unfortunately I couldn't get these to display correctly across platforms while complying with the W3C standards. Maybe they will return when I've done a little more experimentation.

UPDATE (5-Feb-2004): I have managed to restore the rounded corners for Mozilla users using the "-moz-border-radius" style tag.

UPDATE (5-Feb-2004): Forget that, I have had to remove this proprietary tag since it prevented my CSS from validating.

HTML - XHTML transition issues I have come across include:

• Vertical alignment works differently in XHTML. HTML's "valign" tag is transposed with CSS's  "vertical-align" which is simple enough. However, usage is different: "valign" was used within the container (usually a "<td ...>") and vertically aligned everything within that container. Whereas "vertical-align" is used on individual elements and affects only that element.