web/index.html

<!DOCTYPE html>
<html>
<head>
  <!--
    If you are serving your web app in a path other than the root, change the
    href value below to reflect the base path you are serving from.

    The path provided below has to start and end with a slash "/" in order for
    it to work correctly.

    For more details:
    * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base

    This is a placeholder for base href that will be replaced by the value of
    the `--base-href` argument provided to `flutter build`.
  -->
  <base href="$FLUTTER_BASE_HREF">

  <meta charset="UTF-8">
  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
  <meta name="description" content="非官方Picacg">

  <!-- iOS meta tags & icons -->
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="blue">
  <meta name="apple-mobile-web-app-title" content="pica_comic">
  <link rel="apple-touch-icon" href="icons/Icon-192.png">

  <!-- Favicon -->
  <link rel="icon" type="image/png" href="favicon.png"/>

  <title>pica_comic</title>
  <link rel="manifest" href="manifest.json">

  <script>
    // The value below is injected by flutter build, do not touch.
    var serviceWorkerVersion = null;
  </script>
  <!-- This script adds the flutter initialization JS code -->
  <script src="flutter.js" defer></script>
</head>
<body>
<div id="loading">
  <style>
    #loading {
      width: 50px;
      height: 50px;
      position: fixed;
      top: calc(50% - 25px);
      left: calc(50% - 25px);
      z-index: 9999;
    }
    #loading img {
      width: 50px;
      height: 50px;
    }
  </style>
  <img src="loading.gif">
</div>
<script>
  if ('serviceWorker' in navigator) {
    window.addEventListener('flutter-first-frame', function () {
      document.getElementById("loading")?.remove();
      navigator.serviceWorker.register('flutter_service_worker.js');
    });
  }
</script>
  <script>
    window.addEventListener('load', function(ev) {
      // Download main.dart.js
      _flutter.loader.loadEntrypoint({
        serviceWorker: {
          serviceWorkerVersion: serviceWorkerVersion,
        },
        onEntrypointLoaded: function(engineInitializer) {
          engineInitializer.initializeEngine().then(function(appRunner) {
            appRunner.runApp();
          });
        }
      });
    });
  </script>
</body>
</html>