<!DOCTYPE HTML> <html> <!-- https://bugzilla.mozilla.org/show_bug.cgi?id=886646 --> <head> <meta charset="utf-8"> <title>Test for Bug 886646</title> <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/> <style type="text/css"> #scroller { width: 100px; height: 100px; padding: 10px; border: 10px solid black; margin: 10px; overflow: hidden; } #container { width: 50px; height: 50px; } #sticky { position: sticky; width: 10px; height: 10px; overflow: hidden; } </style> </head> <body> <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=886646">Mozilla Bug 886646</a> <div id="display"> <div id="scroller"> <div id="container"> <div id="sticky"></div> </div> </div> </div> <pre id="test"> <script type="application/javascript"> /** Test for Bug 886646 - Offsets for sticky positioning, when accessed through * getComputedStyle(), should be accurately computed. In particular, * percentage offsets should be computed in terms of the scroll container's * content box. */ // Test that percentage sticky offsets are computed in terms of the // scroll container's content box var offsets = { "top": 10, "left": 20, "bottom": 30, "right": 40, }; var scroller = document.getElementById("scroller"); var container = document.getElementById("container"); var sticky = document.getElementById("sticky"); var cs = getComputedStyle(sticky, ""); for (var prop in offsets) { sticky.style[prop] = offsets[prop] + "%"; is(cs[prop], offsets[prop] + "px"); } // ... even in the presence of scrollbars scroller.style.overflow = "scroll"; container.style.width = "100%"; container.style.height = "100%"; var ccs = getComputedStyle(container, ""); function isApproximatelyEqual(a, b) { return Math.abs(a - b) < 0.001; } for (var prop in offsets) { sticky.style[prop] = offsets[prop] + "%"; var basis = parseFloat(ccs[prop == "left" || prop == "right" ? "width" : "height"]) / 100; ok(isApproximatelyEqual(parseFloat(cs[prop]), offsets[prop] * basis)); } </script> </pre> </body> </html>