title: Extjs 3 onchange is not working?
body: <p>I have one textfield in extjs3, In which if i enter 12 digit it should automatically get fire.</p>
  
  <p>we are scanning by barcode scanner, so if digit reach 12 digit it should automatically get fire.</p>
  
  <pre><code>listeners: {
    'change': function(field, newValue, oldValue){
      if(  newValue.length ==12 || newValue.length ==13){
             alert("searchByUpcFunction()");
      }
    }
  }
  </code></pre>
  
  <p>in extjs 4 same thing is working, but not in extjs 3. I need same thing in extjs 3.</p>