code: public boolean executeJs(final String js) {
          try {
              browserPage.performBrowserPageAction(
                      BrowserPageAction.getActionByteBufferForExecuteJS(js));
              return true;
          } catch (final UnsupportedEncodingException e) {
              // NOP
          }
          return false;
      }
docs: Executes the JavaScript at the client browser page. This method is
  equalent to calling <br>
  
  <pre>
  <code>
  try {
  browserPage.performBrowserPageAction(
  BrowserPageAction.getActionByteBufferForExecuteJS(js));
  return true;
  } catch (final UnsupportedEncodingException e) {
  e.printStackTrace();
  }
  </code>
  </pre>
  
  Eg:-
  
  <pre>
  <code>
  tagRepository.executeJs("alert('This is an alert');");
  </code>
  </pre>
  
  This shows an alert in the browser: <b><i>This is an alert</i></b>.
  
  @param js
  the JavaScript to be executed at the client browser page.
  @return true if the given js string is in a supported encoding otherwise
  false. Returning true DOESN'T mean the given js string is valid ,
  successfully sent to the client browser to execute or executed
  successfully.
  @since 2.1.11
  @author WFF