In general, getComputedStyle by itself doesn't cause a reflow. If you get a property from the computed style like `background-color` it won't cause a reflow. It's only if you ask for a property like `width` that it reflows. See http://gent.ilcore.com/2011/03/how-not-to-trigger-layout-in-webkit.html and http://www.phpied.com/the-new-game-show-will-it-reflow/