<!DOCTYPE HTML> <html> <body> <style> body { padding: 100px; width: 5000px; height: 5000px; overflow: scroll; } div { } #parent { background:red; width: 64px; height: 64px; } #child { background:green; position:fixed; width: 32px; height: 32px; } </style> <div id="parent"> <div id="child"> </div> </div> <script type="application/javascript"> if (document.location.search == '?willchange') { document.getElementById("parent").style.willChange = "transform"; } else if (document.location.search == '?ref') { document.getElementById("parent").style.transform = "translateZ(1px)"; } else if (document.location.search == '?noblock') { } document.documentElement.scrollTop = 10; document.documentElement.scrollLeft = 10; </script> </body> </html>