<!DOCTYPE HTML> <html> <!-- https://bugzilla.mozilla.org/show_bug.cgi?id=573255 --> <head> <title>Test for Bug 573255</title> <script src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/> <style type="text/css"> #display:not(.hasSummary) { visibility: hidden } </style> </head> <body> <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=573255">Mozilla Bug 573255</a> <p id="display"></p> <pre id="test"> <script type="application/javascript"> var p = document.getElementById("display"); var cs = getComputedStyle(p, ""); is(cs.visibility, "hidden", "should be visibility:none since it has no class"); p.className = "hasSummary"; is(cs.visibility, "visible", "changing class attribute should remove visibility:hidden"); </script> </pre> </body> </html>