XHTML HowTo

From http://www.w3schools.com (Copyright Refsnes Data)

# XHTML HowTo

## How W3Schools Was Converted To XHTML

W3Schools was converted from HTML to XHTML the weekend of 18. and 19. December 1999, by Hege Refsnes and Ståle Refsnes.

To convert a Web site from HTML to XHTML, you should be familiar with the XHTML syntax rules of the previous chapters. The following steps were executed (in the order listed below):

## A DOCTYPE Definition Was Added

The following DOCTYPE declaration was added as the first line of every page:

    <!DOCTYPE html PUBLIC
    "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

Tip: Your pages must have a DOCTYPE declaration if you want them to validate as correct XHTML.

## Lowercase Tags And Attribute Names

Since XHTML is case-sensitive, and only accept lowercase tags and attributes, a general "find-and-replace" function was executed to replace all uppercase tags with lowercase tags. The same was done for attribute names.

## All Attribute Values Were Quoted

The XHTML 1.0 Recommendation states that all attribute values must be quoted, so every page in W3Schools.com was checked to see that attribute values were quoted.

## Empty Tags: <hr> , <br> and <img>

Empty tags are not allowed in XHTML. The <hr> and <br> tags should be replaced with <hr /> and <br />.

A general "find-and-replace" function was executed to swap the tags.

We decided not to close the <img> tags with </img>, but with /> at the end of the tag. This was done manually.

## The Web Site Was Validated

Finally, all our pages were validated against the official W3C DTD Validator:

W3C XHTML Validator.

A few more errors were found and edited manually. The most common error was missing </li> tags in lists.

We could also have used a converting tool like HTML TIDY.

Dave Raggett's HTML TIDY is a free tool for cleaning up HTML code. It works great on the hard-to-read markup, and it can help to identify where you need to pay further attention on making your pages more accessible to people with disabilities.

From http://www.w3schools.com (Copyright Refsnes Data)