php - click button every second with countdown -

i want click every second example if click 1 time can click after 10 second z

<form name='form' method='post' > <input type="submit" id="add" name="help" > 

you can using javascript below:

<script>     setinterval(function() {       // form button click on every second       document.getelementbyid('add').click();     }, 1000); </script>