Use PHP pre defined $_SERVER
variable :
<html>
<body>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
<input type="text" name="keywords" id="keywordsid" value="sample keyword" />
<input type="submit">
</form>
<?php
if(isset( $_POST['keywords']))
{
echo $_POST['keywords'];
}
?>
</body>
</html>
Here, <?php echo $_SERVER['PHP_SELF']; ?>
helps you to get result on the same page without sending the request to another page.
solved displaying the html entities in php code