Source code for Combining <if> and <define>

<html>
  <head>
    <style type=&quot;text/css&quot;>
    <!--
      body{background-color:#FEFEC9}
      h1{background-color:#FEED87}
    -->
    </style>
  </head>

  <body>
    <h1>Verifying an e-mail address</h1>
    
  <!-- DEFINING FORM TAG -->
    <define tag=&quot;mail-form&quot;>
      <attrib name=&quot;nameval&quot;>&form.name_;</attrib>
      <attrib name=&quot;mailval&quot;>&form.mail_;</attrib>

      <p><b>&_.status;</b><br />&_.mess;</p>

      <form method=&quot;POST&quot;>
        <table>
          <tr><td>Name:</td>
          <td><input type=&quot;input&quot; size=&quot;30&quot; name=&quot;name_&quot;
               value=&quot;&_.nameval;&quot; /></td></tr>
          <tr><td>E-mail:</td>
          <td><input type=&quot;input&quot; size=&quot;30&quot; name=&quot;mail_&quot;
               value=&quot;&_.mailval;&quot; /></td></tr>
          <tr><td><input type=&quot;submit&quot; name=&quot;button&quot;
                   value=&quot;OK&quot; /></td></tr>
        </table>
      </form>  
    </define>

    <if match=&quot;&form.button; = OK&quot;><!-- OK clicked -->

      <set variable=&quot;var.ok&quot; value=&quot;1&quot; />
      <set variable=&quot;var.name_&quot; value=&quot;&form.name_;&quot; />
      <set variable=&quot;var.mail_&quot; value=&quot;&form.mail_;&quot; />
     
      <if variable=&quot;var.name_ = &quot;>
        <append variable=&quot;var.ok&quot; value=&quot;0&quot; />
      </if>
      <if variable=&quot;var.mail_ = &quot;>
        <append variable=&quot;var.ok&quot; value=&quot;0&quot; />
      </if>

      <if variable=&quot;var.ok = 1&quot;><!-- Both not empty -->
        
        <if variable=&quot;var.mail_ = *@*.*&quot;><!-- Success -->
          <p><b>E-mail address verified</b></p>
          <p>Welcome <b>&form.name_;!</b></p>
          <p>E-mail address &quot;&form.mail_;&quot; is OK.</p>
          <form method=&quot;POST&quot;>
            <input type=&quot;submit&quot; name=&quot;button&quot; value=&quot;Again&quot; />
          </form>
        </if>
        <else><!-- Mail not on proper format -->
          <mail-form status=&quot;Error&quot; mess=&quot;E-mail not on format *@*.*&quot;
           mailval=&quot;&quot; />
        </else>
      
      </if>
      <else><!-- name or e-mail empty -->
        <mail-form status=&quot;Error&quot; mess=&quot;You must fill in both name and
         e-mail address.&quot; />
      </else>
    
    </if>
    <else><!-- First time or Again clicked -->
      <mail-form status=&quot;&quot; mess=&quot;Please state your name and e-mail address.&quot; />
    </else>

  </body>
</html>