<!DOCTYPE HTML> <html> <head> <meta charset="utf-8"> <title>Test for style change hint optimizations</title> <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/> <script type="application/javascript"> SimpleTest.waitForExplicitFinish(); function runTests() { /** Test for Bug 1251075 **/ function test_bug1251075_div(id) { var utils = SpecialPowers.DOMWindowUtils; var div = document.getElementById(id); div.style.display = ""; var description = div.style.cssText; div.firstElementChild.offsetTop; var constructedBefore = utils.framesConstructed; div.style.transform = "translateX(10px)"; div.firstElementChild.offsetTop; is(utils.framesConstructed, constructedBefore, "adding a transform style to an element with " + description + " should not cause frame reconstruction even when the element " + "has absolutely positioned descendants"); div.style.display = "none"; } test_bug1251075_div("bug1251075_a"); test_bug1251075_div("bug1251075_b"); SimpleTest.finish(); } </script> </head> <body onload="runTests()"> <div id="bug1251075_a" style="will-change: transform; display:none"> <div style="position: absolute; top: 0; left: 0;"></div> <div style="position: fixed; top: 0; left: 0;"></div> </div> <div id="bug1251075_b" style="filter: blur(3px); display:none"> <div style="position: absolute; top: 0; left: 0;"></div> <div style="position: fixed; top: 0; left: 0;"></div> </div> <pre id="test"> </pre> </body> </html>