moodle/lang/en/help/html.html

<P ALIGN=CENTER><B>Help on writing html</B></P>

<P>When writing HTML in Moodle, you are free to use almost any HTML tags you like
   to produce the effect you want.</p>

<P>Note that scripting (eg Javascript or VB Script) is not allowed, and will be removed
   automatically.</P>

<P>Your code will normally be printed on the page within a table cell, 
   so:

   <UL>
   <LI>there is no need to use any &lt;HEAD> or &lt;BODY> tags
   <LI>be careful about unmatched &lt;/TABLE> tags that may mess up the display.
   </UL>

<p>Smilies (emoticons) will be converted into their graphical equivalent, and 
   bare URLs will be converted into links.</p>

</p>