<!DOCTYPE html>

<html>
<head>
    <meta charset="utf-8">
    <title>Simple Intersection Obsever</title>
    <meta name="viewport" content="width=600">
    <link rel="stylesheet" href="styles.css">
    <script src="script.js"></script>
    <style>
        body {
            font-family: Helvetica;
            height: 6000px;
        }
        
        #target {
            position: absolute;
            left: 60px;
            width: 200px;
            height: 200px;
            top: 2800px;
            padding: 40px;
            box-sizing: border-box;
            font-size: 24pt;
            background-color: rgba(119, 104, 113, 1);
            color: white;
            text-align: center;
            border-radius: 10px;
        }
        
        body .root-margin {
            position: fixed;
            width: 100%;
            height: 100%;
            top: 0;
            left: 0;
            border: 50px solid rgba(0, 0, 0, 0.2);
            box-sizing: border-box;
            pointer-events: none;
        }
    </style>
    <script>
        var observer;   

        function doSetup()
        {
            observer = new IntersectionObserver(intersectedCallback, {
                threshold: [ 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 ],
                rootMargin: '-50px'
            });
            
            let target = document.getElementById('target');
            observer.observe(target);
        }
        window.addEventListener('load', doSetup, false);
    </script>
</head>
<body>

<p>Scroll down to see the target</p>
<div class="results">
<h2>Logging</h2>
<button onclick="clearLog()" class="clear">🗑</button>
<pre id="logging"></pre>
</div>

<div id="target">Target</div>

<div class="root-margin"></div>

</body>
</html>