title: Search Option in Textbox
body: <p>I am using ExtJs4.I have a form in my web application in which there is text box.The scenario is to provide an AJAX like search(like Google) when any key is pressed in the text box.Search will look into a web service and display the result(JSON object) in drop drown.Similar to Google search.</p>
  
  <p>Is there any idea,link or tutorial for doing this? </p>
  
  <p>Thanks</p>