<?php
if ($_POST['submit'] && $_POST['firstname']){
$fname = $_POST['firstname'];
?>
<form method="post" action="populate1.php">
What is your first name?
<INPUT TYPE="text" NAME="firstname" value="<?php echo $fname ?>" max_length=15 size=20>
<input type="submit" name="submit" value="submit">
<form>
<?
}else{
?>
<form method="post" action="populate1.php">
What is your first name?<br>
<INPUT TYPE="text" NAME="firstname" max_length=15 size=15>
<input type="submit" name="submit" value="submit">
<form>
<?
}
?>