title: How to show alert in extjs?
body: <p>While executing the following code in browser it will not shown an alert, its just shown empty page. anything wrong in the following code please help me.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
  &lt;meta http-equiv="Content-Type" content="text.html; charset=utf-8"&gt;
  
  &lt;title&gt; First Program &lt;/title&gt;
  
  &lt;link rel="stylesheet" type="text/css" href ="http://localhost:8080/ext/ext-4.2.1.883/resources/css/ext-all.css"/&gt;
  &lt;script type = "text/javascript" src = "http://localhost:8080/ext/ext-4.2.1.883/ext-all-dev.js"/&gt;
  
  &lt;script type="text/javascript"&gt;
      Ext.onReady(function(){
          //  alert("We are ready to go!");
          Ext.Msg.alert("Hello World");
      });
  &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>