<html>
<head>
<script type="text/javascript">
function datos(dat){
alert('valor '+dat);
}
</script>
<script type="text/javascript">
var i;
var a='<select id=sel name=sel onchange=datos(this.value)>n';
var b;
var c;
for( i=0;i<10;i++){
b+='<option id=idsel value='+i+'>valor '+i+'</option>n';
}
c=a+b;
document.write(c);
</script>
</head>
<body>
</body>
</html>