This is a pretty important concept to get so bear with me. The first example takes a look at what happens when we point the browser to a xml file:

View Example

In this example, the browser parses the document and doesn't recognize the html tags other than as typical xml description tags. So none of the html markup gets applied and the document is not formatted as a list.

But watch what happens when we add an xhtml namespace to the xml file on the <ul> tag like so:

<ul xmlns="http://www.w3.org/1999/xhtml">

To really appreciate what is happening, view the following example, in either a Mozilla based