how to use php server self code example

Example 1: php server self

<form action="<?php echo $_SERVER['PHP_SELF']; ?>"> 
//there is no reason to use this to submit form data to the same page
<form action=""> 
//will do the same thing

Example 2: php post form to self

// Here is how to post form data to self or to the same page & 
// avoid the PHP_SELF exploits at the same time.
<form name="my_form" method="post"
  action="<?php echo htmlentities($_SERVER['PHP_SELF']); ?>"> 
</form>