我只是想得到一张简单的地图(https://developers.google.com/maps/documentation/javascript/examples/map-simple#maps_map_simple-javascript）为我工作的Google Maps JavascriptAPI。

我有这个网页（我已经输入了API密钥，并授予了访问Javascript API的密钥）

<!DOCTYPE html>
<html>
  <head>
    <title>Simple Map</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <style>
        #map {
  height: 100%;
}
    </style>
    <!-- jsFiddle will insert css and js -->
  </head>
  <body>
    <div id="map"></div>

    <!-- Async script executes immediately and must be after any DOM elements used in callback. -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=<MY SPI KEY>&callback=initMap&v=weekly&channel=2"
      async
    ></script>
    <script>
        let map;

function initMap() {
  map = new google.maps.Map(document.getElementById("map"), {
    center: { lat: -34.397, lng: 150.644 },
    zoom: 8,
  });
}
    </script>
  </body>
</html>

我生成了一个html页面，但代码生成的iframe实际上内部有一个空文档。它是

<iframe aria-hidden="true" tabindex="-1" style="z-index: -1; position: absolute; width: 100%; height: 100%; top: 0px; left: 0px; border: medium none;" frameborder="0">
    #document
    <html>
        <head></head>
        <body></body>
    </html>
</iframe>

我肯定错过了一些非常简单和基本的东西——请帮忙