<!doctype html> <!-- https://bugzilla.mozilla.org/show_bug.cgi?id=719515 --> <title>Test for Bug 719515</title> <script src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" href="/tests/SimpleTest/test.css"> <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=719515">Mozilla Bug 719515</a> <p id="display"></p> <div id="content" style="display: none"></div> <pre id="test"> <script> getSelection().collapse(document.body, 0); var range = getSelection().getRangeAt(0); getSelection().extend(document.body, 1); isnot(range, getSelection().getRangeAt(0), "extend() must replace existing ranges, not mutate them"); range = getSelection().getRangeAt(0); getSelection().extend(document.body, 1); isnot(range, getSelection().getRangeAt(0), "extend() must replace existing ranges, not mutate them (even for no-op extend()s"); </script>