title: PHP print message
body: <p>i want to print a message from php code, when the user clicks on button. I added code in php, and placed and if condition that executes when the user clicks on the button.
  Here's the code of default.php:</p>
  
  <pre><code>    &lt;?php
  if (isset($_POST['button1'])) {
  echo '&lt;b&gt;Ok.&lt;/b&gt;';
  }
  ?&gt;
  
  &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head&gt;
  &lt;script type="text/javascript"&gt;
  
  &lt;/script&gt;
  
  &lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8" /&gt;
  &lt;title&gt;PHP3&lt;/title&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
  &lt;p&gt;&amp;nbsp;&lt;/p&gt;
  &lt;p&gt;&amp;nbsp;&lt;/p&gt;
  &lt;p&gt;&amp;nbsp;&lt;/p&gt;
  
  
  &lt;form id="form1" name="form1" method="post" action="default.php"&gt;
    &lt;p&gt;
      &lt;label for="textfield1"&gt;User Name&lt;/label&gt;
      &lt;input type="text" name="username" id="username" /&gt;
    &lt;/p&gt;
    &lt;p&gt;
      &lt;label for="textfield2"&gt;Password&lt;/label&gt;
      &lt;input type="password" name="password" id="password" /&gt;
    &lt;/p&gt;
    &lt;p&gt;
      &lt;input type="submit" name="button1" id="button1" value="Submit"  /&gt;
      &lt;br /&gt;
      &lt;br /&gt;
    &lt;label id="label1"&gt;
    &lt;/label&gt;&lt;/p&gt;
    &lt;p&gt;&amp;nbsp;&lt;/p&gt;
  &lt;/form&gt;
  &lt;p&gt;&amp;nbsp;&lt;/p&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>"Ok" should be printed.
  But i see no "Ok" message get printed.</p>
  
  <p>What can i do?
  Thanks</p>