Dai un'occhiata qui
codice:
<HEAD>
<script>
var reg = new Array();
reg[1] = ["Milano","Como","Sondrio"];
reg[2] = ["Aosta"];
reg[3] = ["Asti","Cuneo","Torino"];
function agg() {
x=document.myform.regioni.selectedIndex;
for(i=0;i<reg[x].length;i++){
tmp=new Option();
tmp.text=reg[x][i];
document.myform.province.options.add(tmp);
}
}
</script>
</HEAD>
<BODY>
<form name="myform">
<select name="regioni" onchange="agg()">
<option></option>
<option>Lombardia</option>
<option>Val d'Aosta</option>
<option>Piemonte</option>
</select>
<select name="province"></select>
</form>
</BODY>
manca qualcosina ma non ho tempo!
ciao