Using PHP, how do you show text entered from a form to the bottom of the same PHP page?

I am trying to show user input at the bottom once submit is pressed

<form name="assignment2" method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">

• php
• html

It sounds like you want AJAX. To do that, the form should post an XMLHttpRequest to the server; JavaScript on the page should then dynamically modify the page DOM to display the text you want.

If you're okay with it being static, just have the PHP page display just the form if there's no input data, and the data if there is input data.

You don't need AJAX or jQuery; you can keep this to simple PHP:

<?php

  echo '<form name="assignment2" method="post" action="'. $_SERVER['PHP_SELF'] .'">';

  // Other form elements

  echo '</form>';

  if(isset($_POST['submit']))
  {
     echo '<input type="text" value="'. $_POST['value_you_want'] .'">';
  }

?>

As Basti has pointed out, you should always be cautious about the possibility of cross-site scripting so you should only really use this code above with non-sensitive data or data which will go nowhere near a database.

Since your form is sent via POST request, all of the form's inputs can be accessed using $_POST. You can simply put them into your inputs as value.

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">

    <input type="text" name="inputname" 
        value="<?php echo @htmlspecialchars($_POST["inputname"]); ?>" />
</form>