repeat different numbers the result when write the while loop [closed]

I wrote a sample code of while loop for a Dice Roll :
if dice is 6 the player is winner, otherwise the program shows just a text

<?php
$a = 0;
while ($a != 6) {
  $a = rand(1,6);
  echo 'The Dice is: ' . $a;
  if ($a == 6) {
    echo '<p>Super! You are the Winner</p>';
  }else{
        echo '<p>Sorry! You can try later...</p>';
  }
}
echo '<p>Thank you for the Play!</p>';
?>

After refresh the page each time during this code, it shows different numbers of result?

And how can I set the specific time of repeating the code just with while?