title: When does reflow happen in a DOM environment?
body: <p>What kinds of activities will trigger reflow of web page with DOM?</p>
  
  <p>It seems there are different points of view. According to <a href="http://www.nczonline.net/blog/2009/02/03/speed-up-your-javascript-part-4/" rel="noreferrer">http://www.nczonline.net/blog/2009/02/03/speed-up-your-javascript-part-4/</a>,  it happens</p>
  
  <ul>
  <li>When you add or remove a DOM node.</li>
  <li>When you apply a style dynamically (such as element.style.width="10px").</li>
  <li>When you retrieve a measurement that must be calculated, such as accessing offsetWidth, clientHeight, or any computed CSS value (via getComputedStyle() in DOM-compliant browsers or currentStyle in IE).</li>
  </ul>
  
  <p>However, according to <a href="http://dev.opera.com/articles/view/efficient-javascript/?page=3" rel="noreferrer">http://dev.opera.com/articles/view/efficient-javascript/?page=3</a>, taking measurement triggers reflow only when there is already reflow action queued.</p>
  
  <p>Does anybody have any more ideas?</p>