How to url encode

<?php
$startDate = '2009/2/20';
$clientID = '1005';

$daturl = urlencode("/report/all_conversions.php?date=".$startDate."&clientid=".$clientID);
?>

<script type="text/javascript" src="/report/ofc/js/swfobject.js"></script>
<script type="text/javascript">
swfobject.embedSWF(
  "/report/ofc/open-flash-chart.swf", "all_conversions_report", "950", "150",
  "9.0.0", "expressInstall.swf",
  {"data-file":"<?php echo $daturl; ?>"}
  );
</script>

<div id="all_conversions_report"></div>