title: KnockoutJS - Update observable value after applybindings
body: <p>I need to update an observable value after creating the view model. Furthermore, I need to update the value directly, in response to an event from a javascript control, without binding an object to that observable. I'm thinking this should be really easy, and that I'm just missing the correct syntax somehow, but I'm just not getting it. </p>
  
  <p>I created a JSFiddle to illustrate what I'm trying to do. 
  <a href="http://jsfiddle.net/toddhd/vwhqU/1/" rel="noreferrer">http://jsfiddle.net/toddhd/vwhqU/1/</a></p>
  
  <p>If you press F12 and watch the console as you run the JSFiddle, you'll see the error(s) being caught. </p>
  
  <pre><code>AppViewModel.firstName('Todd');
  </code></pre>
  
  <p>Trying to update firstname this way tells me that AppViewModel has no function called "firstName".</p>
  
  <pre><code>AppViewModel().firstName('Todd');
  </code></pre>
  
  <p>This way tells me that firstName is undefined.</p>
  
  <p>It may be that I have to call Apply Bindings again, but I don't really want to do that just to update a single value. </p>
  
  <p>What am I missing?</p>