title: Getting property value is undefined or null error for JavaScript call in Dynamics CRM 2011
body: <p>Just started with Javasript + Dynamics 2011 today and got stuck at the beginning itself. I've been trying simple steps as follow
  1. Change the value on radio button
  2. Call a function from Javascript, which will set two field enabled and disabled</p>
  
  <p>Code is as follows</p>
  
  <pre><code>function navenabled()
  {
  
      var navdata = Xrm.Page.getAttribute("new_currentnavclient").getValue;
  
      if (navdata == true)
      {
          Xrm.Page.getControl(“new_noofusers”).setDisabled(true);
          Xrm.Page.getControl(“new_navversion”).setDisabled(true);
      }
      else
      {
          Xrm.Page.getControl(“new_noofusers”).setDisabled(false);
                  Xrm.Page.getControl(“new_navversion”).setDisabled(false);
      }
  
  }
  </code></pre>
  
  <p>I'm getting the following error, when changing the value on 'Current Nav Client' field</p>
  
  <p><img src="https://i.stack.imgur.com/21SWw.png" alt="enter image description here"></p>
  
  <p>Also see the steps that I have performed for JavaScript call</p>
  
  <p><img src="https://i.stack.imgur.com/2A1mz.png" alt="enter image description here"></p>
  
  <p>Can someone please tell where I'm doing wrong.</p>