title: Puppeteer waitForSelector on multiple selectors
body: <p>I have Puppeteer controlling a website with a lookup form that can either return a result or a "No records found" message. How can I tell which was returned? 
  waitForSelector seems to wait for only one at a time, while waitForNavigation doesn't seem to work because it is returned using Ajax.
  I am using a try catch, but it is tricky to get right and slows everything way down.</p>
  
  <pre><code>try {
      await page.waitForSelector(SELECTOR1,{timeout:1000}); 
  }
  catch(err) { 
      await page.waitForSelector(SELECTOR2);
  }
  </code></pre>