title: Get title, nav_title and subtitle
body: <p>I want to print the fields <code>title</code>, <code>nav_title</code> and <code>subtitle</code> with Typoscript. I saw that there are several possibilities. E.g. <code>data</code>, <code>field</code>, <code>levelfield</code>, <code>leveltitle</code>, ...</p>
  
  <p>Currently I'm using this code (because the only one which works for me so far):</p>
  
  <pre><code>lib.heading = TEXT
  lib.heading.dataWrap = &lt;p class="title"&gt; {leveltitle:0} &lt;/p&gt;
  </code></pre>
  
  <p>but I want something with alternatives like this</p>
  
  <p><code>stdWrap.field = subtitle // nav_title // title</code></p>
  
  <p>What is the correct way of retrieving these fields?</p>
  
  <p>Edit:</p>
  
  <pre><code>[userFunc = user_isMobile]
  
  page.headerData.10 = TEXT
  page.headerData.10.value (
      // ...
  )
  
  // ...
  
  lib.heading = TEXT
  #lib.heading.dataWrap = &lt;p class="title"&gt; {leveltitle:0} &lt;/p&gt;
  
  lib.heading {
    field = title 
    wrap = &lt;p class="title"&gt; | &lt;/p&gt;
  }
  
  lib.subpages = HMENU
  lib.subpages {
    // ...
  }
  
  [global]
  </code></pre>
  
  <p>The userfunction itself is a function in a php script (user_mobile.php). It makes a user agent detection for mobile devices and returns true or false.</p>