You can use this;
<script>
window.onload = function() {
setInterval(function(){
document.frm.submit();
},5000);
}
</script>
HTML:
<form id="myform" method="post" name="myform">
<?php $id = $_POST['id']; $id=$id+1; ?>
<input type="hidden" name="id" value="<?php echo $id; ?>"/>
</form>
This will submit form every 5 secs after page loaded
Here is a working demo: jsfiddle