title: How to Handle errors on ExtJs
body: <p>I want to be able to catch any error thrown on my screen. So far my  code is this:</p>
  
  <pre><code>Ext.application({
      errorHandler:function(err){
          alert(err.msg);
          return true;
      },
      requires: [
          'Ext.ux.ajax.JsonSimlet',
          'Ext.ux.ajax.SimManager'
      ],
  
      views: [
          'Admin.view.something', 
          'Admin.view.somethingController'
      ],
  
      name: 'Admin',
  
      launch : function() {Ext.create('Admin.view.something');
      Ext.Error.notify = false;
      Ext.Error.handle = this.errorHandler;
      }
  });
  </code></pre>
  
  <p>The problem is, I have some objects that may be undefined. If I do something like undefined.properties, the error handling doesn't catch it.</p>
  
  <p>I know about functions like "Ext.isDefined()", but for this case I really need to handle all generic errors in the same way.</p>