title: Uncaught TypeError: undefined is not a function in sencha touch
body: <p>I am new in sencha touch. So I am just try the code from <a href="http://www.packtpub.com/article/creating-simple-application-sencha-touch" rel="nofollow noreferrer">this article</a>.<br>
  The problem is when i run  this code  it gives this error:</p>
  
  <blockquote>
    <p>Uncaught TypeError: undefined is not a function  (TouchStart.js:2)</p>
  </blockquote>
  
  <p><code>TouchStart.js :</code></p>
  
  <pre><code>// JavaScript Document
  new Ext.Application({
  name: 'Chat',
  launch: function() {
  var hello = new Ext.Container({
  fullscreen: true,
  html: '&lt;div id="hello"&gt;Hello World&lt;/div&gt;'
    });
  
  this.viewport = hello;
    }
  });
  </code></pre>
  
  <p>I try <a href="https://stackoverflow.com/questions/10888143/sencha-touch-uncaught-typeerror-undefined-is-not-a-function">this</a>  but not found solution. so what is the problem?Thanks in advance.  </p>