css/css-variables/variable-first-line.html

<!DOCTYPE html>
<html>
<head>
    <title>CSS Variables with ::first-line pseudo-element.</title>

    <meta rel="author" title="Kevin Babbitt">
    <meta rel="author" title="Greg Whitworth">
    <link rel="author" title="Microsoft Corporation" href="http://microsoft.com" />
    <!-- This is not directly specified in the spec but should work -->
    <link rel="help" href="http://www.w3.org/TR/css-variables-1/#defining-variables">

    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <style>
        div {
            width: 500px;
        }

        #div1::first-line {
            color: var(--my-color);
            --my-color: rgb(0, 0, 255);
        }

        #div2::first-line {
            font-size: var(--my-font-size);
            --my-font-size: 25px;
        }

        #div3::first-line {
            font-weight: var(--my-font-weight);
            --my-font-weight: 900;
        }

        #div4::first-line {
            color: var(--my-color1);
            --my-color1: var(--my-color2);
            --my-color2: rgb(0, 0, 255);
        }
    </style>
</head>
<body>
    <div id="div1">CSS variable defining 'color' property should be applied to ::first-line and its color should be blue.</div>
    <br />
    <div id="div2">CSS variable defining 'font-size' property should be applied to ::first-line and its font-size should be 25px.</div>
    <br />
    <div id="div3">CSS variable defining 'font-weight' property should be applied to ::first-line and its font-weight should be 900.</div>
    <br />
    <div id="div4">CSS variable referencing another CSS variable that defines 'color' property should be applied to ::first-line and its color should be blue.</div>

    <script>
        "use strict";

        let templates = [
            { elementId: "div1", property: "color", expectedValue: "rgb(0, 0, 255)", testName: "color" },
            { elementId: "div2", property: "font-size", expectedValue: "25px", testName: "font-size" },
            { elementId: "div3", property: "font-weight", expectedValue: "900", testName: "font-weight" },
            { elementId: "div4", property: "color", expectedValue: "rgb(0, 0, 255)", testName: "nested color" },
        ];

        templates.forEach(function (template) {
            test( function () {
                var elem = document.getElementById(template.elementId);
                var actualValue = window.getComputedStyle(elem, ':first-line').getPropertyValue(template.property);
                assert_equals(template.expectedValue, actualValue);
            }, template.testName);
        });
    </script>
</body>
</html>