Ho smanettato un pò e ce l'ho fatta...
(con javascript......)

A chi servisseeee!!!!!!

<html>
<body>
<script language="JavaScript">

function throwdice(){
var randomdice=Math.round(Math.random()*5)
document.dadi.lancio.value = randomdice+1
}
</script>


<form name="dadi">
<input type="button" value="Dado" onClick="throwdice()">
<input type="text" size="4" name="lancio">
</form>
</body>
</html>