devi fare un return della variabile filmato, altrimenti la funzione swf non torna nulla:
codice:
<script language="javascript" type="text/javascript">
function swf(film){
var filma = '<object classid="clsid27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0" width="500" height="600" title="">';
var filma2 = filma + '<param name="movie" value="swf/'+film+'.swf" />';
var filma3 = filma2 + '<param name="quality" value="high" />';
var filma4 = filma3 + '<embed src="swf/'+film+'.swf" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" width="500" height="600">';
var filma5 = filma4 + '</embed>';
var filmato = filma5 + '</object>';
return filmato;}
</script>