/* CSS Document */
body {
    font:12px arial;
    color: #222;
    text-align:center;
    padding:35px; }
  
form, p, span {
    margin:0;
    padding:0; }
  
input { font:12px arial; }
  
a {
    color:#0000FF;
    text-decoration:none; }
  
    a:hover { text-decoration:underline; }
  
#wrapper, #loginform {
    margin:0 auto;
    padding-bottom:25px;
    background:#EBF4FB;
    width:504px;
    border:1px solid #ACD8F0; }
  
#loginform { padding-top:18px; }
  
    #loginform p { margin: 5px; }
  
#chatbox {
    text-align:left;
    margin:0 auto;
    margin-bottom:25px;
    padding:10px;
    background:#fff;
    height:270px;
    width:430px;
    border:1px solid #ACD8F0;
    overflow:auto; }
  
#usermsg {
    width:395px;
    border:1px solid #ACD8F0; }
  
#submit { width: 60px; }
  
.error { color: #ff0000; }
  
#menu { padding:12.5px 25px 12.5px 25px; }
  
.welcome { float:left; }
  
.logout { float:right; }
  
.msgln { margin:0 0 2px 0; }


<?
session_start();
 
function loginForm(){
    echo'
    <div id="loginform">
    <form action="index.php" method="post">
        <p>Please enter your name to continue:</p>
        <label for="name">Name:</label>
        <input type="text" name="name" id="name" />
        <input type="submit" name="enter" id="enter" value="Enter" />
    </form>
    </div>
    ';
}
 
if(isset($_POST['enter'])){
    if($_POST['name'] != ""){
        $_SESSION['name'] = stripslashes(htmlspecialchars($_POST['name']));
    }
    else{
        echo '<span class="error">Please type in a name</span>';
    }
}
?>

<?php
if(!isset($_SESSION['name'])){
    loginForm();
}
else{
?>