<?php
$ucode = rand(1000,10000);
$password = rand(100000,1000000);
?>
/* Form
<form method="post" action="form.php" id="Checker">
<input type="text" name="ucode" value="DF<?=$ucode?>" />
<input type="text" name="password" value="<?=$password?>" />
<input type="submit" name="send" value="SEND" />
</form>