Control stacking order of Flash and DHTML elements with z-index. Use z-index negative value to put objects behind and positive value to bring items to front.
To make items visible below Flash animation you have to export SWF file in windowless mode (WMODE=transparent).
The following example demonstrates 3 objects, Flash animation with z-index:0, "Text BELOW" (z-index:-1) and "Text ABOVE" (z-index:1)
Create Flash Animation
Export Flash SWF File
<HTML>
<BODY>
<DIV STYLE="z-index: 1; position:relative; left:100; top:165;"><b><font color=blue>Text ABOVE the Flash</b></font></DIV>
<DIV STYLE="z-index: 0; position:relative">
<DIV STYLE="z-index: -1; position:relative; left:50; top:95;"><b><font color=red>Text BELOW the Flash</b></font></DIV>
<OBJECT CLASSID="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
WIDTH="300" HEIGHT="240"
CODEBASE="http://active.macromedia.com/flash5/cabs/swflash.cab#version=5,0,0,0">
<PARAM NAME="MOVIE" VALUE="Untitled-1.swf">
<PARAM NAME="PLAY" VALUE="true">
<PARAM NAME="LOOP" VALUE="true">
<PARAM NAME="WMODE" VALUE="transparent">
<PARAM NAME="QUALITY" VALUE="high">
<EMBED SRC="Untitled-1.swf" WIDTH="300" HEIGHT="240" PLAY="true" LOOP="true" WMODE="transparent" QUALITY="high"
PLUGINSPAGE="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash">
</EMBED>
</OBJECT>
</DIV>
</BODY>
</HTML>