By default, Flash only supports a small subset of HTML in htmlText fields Reference:

• Anchor tag (<a>)
• Bold tag (<b>)
• Break tag (<br>)
• Font tag (<font>)
• Image tag (<img>)
• Italic tag (<i>)
• List item tag (<li>)
• Paragraph tag (<p>)
• Text format tag (<textformat>)
• Underline tag (<u>)

Flex-htmlFilter can be utilised to extend the HTML support of htmlText fields by enabling the use of:

• Unordered list tag (<ul>)
• Ordered list tag (<ol>)
• Table tag (<table>)
• Table row tag (<tr>)
• Table column tag (<td>)
• Table header column (<th>)
• Table caption tag (<caption>)
• Heading tags (<h1-6>)

As well as this, it allows the use of some "custom" tags and some custom attributes of the above tags.

See http://flex-htmlfilter.googlecode.com/svn/trunk/base/com/htmlFilter/Supported%20Tags%20and%20Attributes for a full list of the supported tags and attributes. (when I have time, I'll make into a wiki page and update it)

An old (look below for the new one) interactive example can be found at http://stephen-m.appspot.com/htmlFilter (Note this is the old version, keep reading this page!)

NEWS

Since April 16 2009, trunk contains a new version of flex-htmlfilter. Unfortunately I have little time to document what has been added and changed, however I do plan to do this in the future.

However, one major change is the use of preprocessing in the code. Please refer to this wiki page for more details.

For now, an online demo can be found here http://stephen-m.appspot.com/htmlFilterNew