title: ExtJS Button text change
body: <p>I am designing a button in <strong>ExtJS</strong> with text <code>Show</code>, when I click on <code>button</code>, I want to change text as <code>Hide</code></p>
  
  <p>How can I handle this.</p>
  
  <p>Plz Help me.</p>
  
  <p>Thanks in advance</p>