title: Using image on login button
body: <p>I have the following code sample login.php:</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
  &lt;title&gt;Modul 15 - Membuat Otentikasi User&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;h2&gt;Form Login&lt;/h2&gt;
  Anda belum terdaftar sebagai user ?
  [ &lt;a href="register.php"&gt;Daftar sekarang&lt;/a&gt;]
  &lt;br /&gt;&lt;br /&gt;
  &lt;form action="do_login.php" method="post"&gt;
  &lt;table&gt;
  &lt;tr&gt;
      &lt;td&gt;ID User&lt;/td&gt;
      &lt;td&gt;&lt;input type="textfield" name="id" maxlength="15" size="25" /&gt;&lt;/td&gt;
  &lt;/tr&gt;
  &lt;tr&gt;
      &lt;td&gt;Password&lt;/td&gt;
      &lt;td&gt;&lt;input type="password" name="pwd" maxlength="15" size="25" /&gt;&lt;/td&gt;
  &lt;/tr&gt;
  &lt;tr&gt;
      &lt;td&gt;&amp;nbsp;&lt;/td&gt;
      &lt;td&gt;&lt;input type="image" src="login_btn.png" name="login" /&gt;&lt;/td&gt;
  &lt;/tr&gt;
  &lt;/table&gt;
  &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>and the code for handle the process of login as do_login.php:</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
  &lt;title&gt;Modul 15 - Membuat Otentikasi User&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;?php
  if (isset($_POST['login'])) 
  {
  $id = $_POST['id'];
  $pwd = $_POST['pwd'];
  $database = "dbxxxxxx";
  $hostname = "172.xx.xx.xx";
  $port = "50000";
  
  $conn_string = "DRIVER={IBM DB2 ODBC DRIVER};DATABASE=$database;" .
  "HOSTNAME=$hostname;PORT=$port;PROTOCOL=TCPIP;UID=$id;PWD=$pwd;";
  $conn = db2_connect($conn_string, '', '');
  if ($conn) 
  {
      echo "Connection succeeded.";
      db2_close($conn);
  }
  else 
  {
      echo "Connection failed.";
  }
  }
  else
  {
  echo "Login variable not set !!!";
  }
  ?&gt;
  &lt;/body&gt;
  &lt;/html&gt; 
  </code></pre>
  
  <p>The code always returns "<strong>Login variable not set !!!</strong>". Why does this happen? Are there something wrong with my codes ? Can someone help me please ...</p>