index.html

<html lang="en">
<head>
    <meta charset="utf-8">
    <script src="https://cesium.com/downloads/cesiumjs/releases/1.80/Build/Cesium/Cesium.js"></script>
    <link href="https://cesium.com/downloads/cesiumjs/releases/1.80/Build/Cesium/Widgets/widgets.css" rel="stylesheet">
</head>
<body>
    <div id="cesiumContainer" style="width: 100%; height:100%"></div>
    <script src="load_cesium.js"></script>
</body>
</html>