<!DOCTYPE html> <!-- Any copyright is dedicated to the Public Domain. - http://creativecommons.org/publicdomain/zero/1.0/ --> <!-- Percentage sticky offsets should be computed correctly when - the scroll container is auto-sized --> <html> <head> <link rel="author" title="Corey Ford" href="mailto:cford@mozilla.com"> <link rel="match" href="scrollframe-auto-1-ref.html"> <style> body { /* even on initial reflow */ overflow: scroll; } #scroll { height: auto; overflow: hidden; border: 1px solid black; } #sticky { position: sticky; height: 10px; top: 50%; background-color: black; } .fill { height: 200px; } </style> <body> <div id="scroll"> <div id="sticky"></div> <div class="fill"></div> </div> </body> </html>