<!doctype html>
<html>
<head>
<title>Test for Bug 35014 - Modifying UA rules from page JS crashes</title>
<script>
if (window.testRunner)
    testRunner.dumpAsText();

function test()
{
    var cssRulesList = window.getMatchedCSSRules(document.body, "", false);
    if (cssRulesList) 
    {
        var styleToChange = cssRulesList[0].style;
        var originalMarginTop = styleToChange.marginTop;
        styleToChange.marginTop = "200px";
        styleToChange.marginTop = originalMarginTop;
        document.getElementById("result").innerHTML = "FAIL";
    }
}
</script>
</head>
<body onload="test()">
<div id="result">
PASS
</div>
</body>
</html>