Hallo.

vielleicht mache ich was falsch.

hier den php datei. Endung ist php

<?php
<header>
  Rhein-Main-Elektrotechnik.html
</header>
<nav>
  <ul id="nav">
   <li><a>HauptMenu 1</a>
       <ul class="level1">
           <li><a>level 1</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.1.2</a></li>
                   <li><a href="">Menu 1.1.3</a></li>
               </ul>
           </li>
    <li><a>Elektroinstallationen</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.1.2</a></li>
                   <li><a href="">Menu 1.1.3</a></li>
               </ul>
           </li>
           <li><a>Menu 1.2</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.2.2</a></li>
                   <li><a href="">Menu 1.2.3</a></li>
               </ul>
           </li>
   <li><a>Menu 1.2</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.2.2</a></li>
                   <li><a href="">Menu 1.2.3</a></li>
               </ul>
           </li>
   <li><a>Menu 1.2</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.2.2</a></li>
                   <li><a href="">Menu 1.2.3</a></li>
               </ul>
           </li>
   <li><a>Menu 1.2</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.2.2</a></li>
                   <li><a href="">Menu 1.2.3</a></li>
               </ul>
           </li>
   <li><a>Menu 1.2</a>
               <ul class="level2">
                   <li><a href="">level 2</a></li>
                   <li><a href="">Menu 1.2.2</a></li>
                   <li><a href="">Menu 1.2.3</a></li>
               </ul>
           </li>
       </ul>
   </li>
   <li><a>HauptMenu 2</a>
       <ul class="level1">
          <li><a> Elektroinstallationen</a>

<ul class="level2">
                   <li><a>Menu 2 level 2</a>
                       <ul class="level3">
                           <li><a href="">Menu level 3</a></li>
                           <li><a href="">Menu 2.2.1.2</a></li>
                           <li><a href="">Menu 2.2.1.3</a></li>
                       </ul>
                   </li>

</ul>
           </li>
       </ul>
   </li>
   <li><a>HauptMenu 2</a>
       <ul class="level1">
          <li><a> Elektroinstallationen</a>

<ul class="level2">
                   <li><a>Menu 2 level 2</a>
                       <ul class="level3">
                           <li><a href="">Menu level 3</a></li>
                           <li><a href="">Menu 2.2.1.2</a></li>
                           <li><a href="">Menu 2.2.1.3</a></li>
                       </ul>
                   </li>

</ul>
           </li>
       </ul>
   </li>
   <li><a>HauptMenu 2</a>
       <ul class="level1">
          <li><a> Elektroinstallationen</a>

<ul class="level2">
                   <li><a>Menu 2 level 2</a>
                       <ul class="level3">
                           <li><a href="inhalt.html" target="daten">Menu level 3</a></li>
                           <li><a href="">Menu 2.2.1.2</a></li>
                           <li><a href="">Menu 2.2.1.3</a></li>
                       </ul>
                   </li>

</ul>
           </li>
       </ul>
   </li>
   <li><a href="">Menu 4</a></li>
   <li><a href="">Menu 5</a></li>
</ul>
</nav>
?>