[JavaScript] Calcolare la distanza in giorni tra due date

<script type="text/javascript">
function startEndDate() {
from='21/04/2010'; //prima data
to='25/04/2010'; //seconda data

var fromArray = from.split('/');
fromdate = new Date(fromArray[2], fromArray[1]-1, fromArray[0]);

var toArray = to.split('/');
todate = new Date(toArray[2], toArray[1]-1, toArray[0]);

alert((todate-fromdate)/86400000);

}
</script>