XHTML is a markup language used in content management systems and has the same capabilities as HTML but uses stricter syntax.  It is the successor to HTML 4. XHTML can be described as a mixture of classic (HTML) and cutting-edge (XML). It looks and works much like HTML but is based on the web’s super markup language (XML). XHTML raises HTML coding to XML standards. This brings changes in the following areas:

.  XHTML documents must be well formed and elements must have closer tags
.  Attribute values must be in quotes
.  All tag names in XHTML are in lower case as XML tags are case sensitive

The motivation behind the use of XHTML is to provide web documents that can be shared across communities in desktops, televisions, and mobile phones, and which are rich enough for simple content authoring. Since web‘s development is going toward XML coding, it is important the right coding techniques are used. Web developers who want their sites to work well in modern browsers and non-traditional devices and even continue to work well in the future, use XHTML to author their sites. Old pages can also be converted to XHTML .

XHTML compliant code helps DotNetNuke websites display more reliably in both browsers and mobile devices such as smartphones.

When using CSS with DNN, it improves performance, accessibility, search engine results and reduces the bandwidth of DNN skins. However, you need to ensure your code follows XHTML standards. For example, if you miss a closing tag in your XHTML code, it will completely ruin your CSS skin. CSS brings the difference as using standard settings of DNN and table based skin even if you have XHTML compliant code does make any difference.

XHTML standards needs to be adhered in DNN web development

When a web designer installs a module into a pure CSS skin that contains missing closing tags or other non-compliant code, it may lead to corruption of the layout of the skin. An example of a missing tag is <br>. The complete tag should be <br />.  When a layout of skin is corrupt, you will not be able to use any module with the skin until all non-compliant code is fixed.

Web designers using the DNN content management system should learn how to create XHTML compliant code and learn to follow the required format if they want to achieve top quality designs for their websites. Even if you are a beginner who is only creating table based skins, you should start learning early how to venture into pure CSS environment. This will make it a much easier transition when you finally come of age and starts designing complex websites. You can implement XHTML compliant code when developing modules to future proof them so that they can be used in as many configurations as possible.