How to make the distance between the player’s nickname in the chat and his message?

Chat itself:

<iframe name='chatWindow' id='chatWindow' src ="iframe.php" width="1265" height="400"></iframe>   
<form action="iframe.php" method="post" id="form" target='chatWindow' >
<p>:<input name="message" type="text" size="75" maxleght="255">
<input name="submit" type="submit" value="OK">

And this is an iframe:

<script type="text/javascript">
    setTimeout("window.location.reload()",15000); //    15 
</script>

and

<?php
  session_start();
  if (isset($_POST['message'])) {
      $message = $_POST['message'];
  }
  $db = mysql_connect("...", "...", "...");
  mysql_select_db("...", $db);
  if (trim($message) != "") {
      mysql_query("INSERT INTO messages (message,username) VALUES ('$message','{$_SESSION['username']}')");
  }
  $result = mysql_query("SELECT * FROM messages");
  while ($row = mysql_fetch_array($result)) {
      echo "<br>";
      echo "{$row['message']}";
      echo $row['username'];
  }
?>

And the chat script:

<script>
jQuery(function ($) {
    $("#form").onsubmit(function (event) {
        var message = $("input[name='message']", form).value()
        if (message) {
            event.preventDefault();
            return false;
        }
        return true;
    });
    $("#form input[name='message']").bind('change keydown keypress', function (event){
        var text = $(this).value().replace(/^\s+/, "").replace(/\s+$/, "");
        $("#form input[type='submit']").prop("disabled", text == "");
    });
});
</script>

Answer 1, authority 100%

while ($row = mysql_fetch_array($result)) {
      echo "<br>";
      echo "{$row['message']}";
      echo "&nbsp;".$row['username']; //&nbsp; -  . 
  }

This is the simplest option.
P.S. Do you know Vlad?