title: how to run a scheduled task in selenium webdriver
body: <p>I want to run a </p>
  
  <blockquote>
    <p>timer</p>
  </blockquote>
  
  <p>in selenium webdriver,I don't want to use multi-thread, and the timer cann't block(like setInterval in js),and now I have no idea.</p>
  
  <p>Eg: check a element class per 10 seconds.</p>