css/cssom/CSSStyleSheet.html

<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>CSSOM - CSSStyleSheet interface</title>
    <link rel="help" href="https://drafts.csswg.org/cssom/#the-cssstylesheet-interface">
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <style id="my-stylesheet">
        body { width: 50%; }
        #foo { height: 100px; }
    </style>

    <script>
    test(function () {
        var styleSheet = document.styleSheets[0];
        styleSheet.cssRules[0].randomProperty = 1;
        styleSheet.cssRules[1].randomProperty = 2;

        assert_equals(styleSheet, document.getElementById("my-stylesheet").sheet, "CSSStyleSheet and LinkStyle's sheet attribute");
        assert_equals(styleSheet.cssRules.length, 2, "CSSStyleSheet cssRules attribute");
        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute");
        assert_equals(styleSheet.cssRules[1].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute");
        assert_equals(styleSheet.cssRules[2], undefined, "CSSStyleSheet cssRules attribute");

        styleSheet.insertRule("#bar { margin: 10px; }", 1);
        assert_equals(styleSheet.cssRules.length, 3, "CSSStyleSheet cssRules attribute after insertRule function");
        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute");
        assert_equals(styleSheet.cssRules[1].cssText, "#bar { margin: 10px; }", "CSSStyleSheet cssRules attribute after insertRule function");
        assert_equals(styleSheet.cssRules[2].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute after insertRule function");
        assert_equals(styleSheet.cssRules[0].randomProperty, 1, "[SameObject] cssRules attribute after insertRule function");
        assert_equals(styleSheet.cssRules[2].randomProperty, 2, "[SameObject] cssRules attribute after insertRule function");

        styleSheet.deleteRule(1);
        assert_equals(styleSheet.cssRules.length, 2, "CSSStyleSheet cssRules attribute after deleteRule function");
        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute after deleteRule function");
        assert_equals(styleSheet.cssRules[1].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute after deleteRule function");
        assert_equals(styleSheet.cssRules[2], undefined, "CSSStyleSheet cssRules attribute after deleteRule function");
        assert_equals(styleSheet.cssRules[0].randomProperty, 1, "[SameObject] cssRules attribute after deleteRule function");
        assert_equals(styleSheet.cssRules[1].randomProperty, 2, "[SameObject] cssRules attribute after deleteRule function");
    });
    </script>
</head>
</html>