allow you to access the values of forms that are submitted to a PHP script code example
Example: php post variables to another page with submit button php
<html>
<form id="form" action="webAddressYouWantToRedirectTo.php" method="POST">
<input type="hidden" name="expectedPOSTVarNameOnTheOtherPage" value="<?php echo $varYouMadePreviouslyInProcessing ?>">
</form>
<script>
document.getElementById("form").submit();
</script>
</html>