<!DOCTYPE html> <title>position:sticky top constraint should behave correctly for <th> elements</title> <link rel="match" href="position-sticky-table-th-top-ref.html" /> <link rel="help" href="https://www.w3.org/TR/css-position-3/#sticky-pos" /> <meta name="assert" content="This test checks that the position:sticky top constraint behaves correctly for <th> elements" /> <style> table { border-collapse:collapse; } td, th { padding: 0; } td > div, th > div { height: 50px; width: 50px; } .group { display: inline-block; position: relative; width: 150px; height: 200px; } .scroller { position: relative; width: 100px; height: 150px; overflow-x: hidden; overflow-y: auto; } .prepadding { height: 100px; } .postpadding { height: 250px; } .indicator { position: absolute; background-color: red; left: 0; height: 50px; width: 50px; } .sticky { position: sticky; top: 25px; background-color: green; } </style> <script> window.addEventListener('load', function() { document.getElementById('scroller1').scrollTop = 50; document.getElementById('scroller2').scrollTop = 125; document.getElementById('scroller3').scrollTop = 250; }); </script> <div>You should see three green boxes below. No red should be visible.</div> <div class="group"> <div id="scroller1" class="scroller"> <div class="indicator" style="top: 100px;"></div> <div class="prepadding"></div> <table> <thead> <tr> <th class="sticky"><div></div></th> </tr> </thead> <tbody> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> </tbody> </table> <div class="postpadding"></div> </div> </div> <div class="group"> <div id="scroller2" class="scroller"> <div class="indicator" style="top: 150px;"></div> <div class="prepadding"></div> <table> <thead> <tr> <th class="sticky"><div></div></th> </tr> </thead> <tbody> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> </tbody> </table> <div class="postpadding"></div> </div> </div> <div class="group"> <div id="scroller3" class="scroller"> <div class="indicator" style="top: 250px;"></div> <div class="prepadding"></div> <table> <thead> <tr> <th class="sticky"><div></div></th> </tr> </thead> <tbody> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> <tr><td><div></div></td></tr> </tbody> </table> <div class="postpadding"></div> </div> </div>