Just open frontpage.tpl.php
change this
<script type="text/javascript">
$(document).ready(function() {
$("#refresh").click(function(e) {
e.preventDefault();
$("#content-watched-videos").load("<?php echo RELATIVE_URL; ?>/ajax/?s=watched");
});
});
</script>
<script>
var refreshId = setInterval(function()
{
$('#content-watched-videos').fadeOut("slow").load('<?php echo RELATIVE_URL; ?>/ajax/?s=watched').fadeIn("slow");
}, 20000);
</script>