Content - a4e89b37657361358f1b854e94c8d6b2a30d8c6c - 5b70372/paint-timing/first-contentful-image.html

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Tip revision: ad6018d3a07c0903d6b00c72cd9bd0541d607c2b authored by Ms2ger on 27 February 2018, 14:20:49 UTC
Add a section on landing changes.

Tip revision: ad6018d

first-contentful-image.html

<!DOCTYPE html>
<head>
<title>Performance Paint Timing Test: FCP due to image</title>
</head>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="image"></div>

<script>
async_test(function (t) {
    const img = document.createElement("IMG");
    img.src = "resources/circles.png";
    img.onload = function() {
        function testPaintEntries() {
            const bufferedEntries = performance.getEntriesByType('paint');
            if (bufferedEntries.length < 2) {
                t.step_timeout(function() {
                    testPaintEntries();
                }, 20);
                return;
            }
            t.step(function() {
                assert_equals(bufferedEntries.length, 2, "There should be two paint timing instances.");
                assert_equals(bufferedEntries[0].entryType, "paint");
                assert_equals(bufferedEntries[0].name, "first-paint");
                assert_equals(bufferedEntries[1].entryType, "paint");
                assert_equals(bufferedEntries[1].name, "first-contentful-paint");
                t.done();
            })
        }
        t.step(function() {
            testPaintEntries();
        });
    };
    document.getElementById('image').appendChild(img);
}, "First contentful paint fires due to image render.");
</script>
</body>
</html>

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