<!DOCTYPE html>
<html>
<head>
<script>
    window.onload = function() {
        // fetch offsetTop to force a layout
        document.body.offsetTop;

        var el = document.querySelector('#add-shape-margin .shape');
        el.className = 'shape margin50';

        el = document.querySelector('#change-shape-margin .shape');
        el.className = 'shape margin25';

        el = document.querySelector('#remove-shape-margin .shape');
        el.className = 'shape';
    }
</script>
<style>
    .container {
        width: 200px;
        height: 200px;
        overflow-wrap: break-word;
        border: 2px solid blue;
        font: 50px/1 Ahem, sans-serif;
        color: green;
        overflow: hidden;
    }
    .shape {
        float: left;
        position: relative;
        width: 100px;
        height: 100px;
        -webkit-shape-outside: inset(0 100% 100% 0);
    }
    .shape::before {
        position: absolute;
        display: block;
        top: 0; left: 0;
        width: 0;
        height: 0;
        background-color: blue;
        content: ' ';
    }

    .margin25 {
        -webkit-shape-margin: 25px;
    }
    .margin25::before {
        width: 25px;
        height: 25px;
    }

    .margin50 {
        -webkit-shape-margin: 50px;
    }
    .margin50::before {
        width: 50px;
        height: 50px;
    }
</style>
</head>
<body>
    <p>When shape-margin is modified dynamically, content affected by the shape's contour should relayout. For each test, you should see green blocks separated by white space, wrapping around a blue square in the upper left. This test requires the Ahem font.</p>

    <p>Setting shape-margin with no prior entry</p>
    <div id='add-shape-margin' class='container'><div class='shape'></div>x x x x x x x x x x</div>

    <p>Setting shape-margin with a prior entry</p>
    <div id='change-shape-margin' class='container'><div class='shape margin50'></div>x x x x x x x x x x</div>

    <p>Removing shape-margin with a prior entry</p>
    <div id='remove-shape-margin' class='container'><div class='shape margin50'></div>x x x x x x x x x x</div>
</body>
</html>