'我有一个Unity 3D项目，我可以开着叉车到处走，我想添加一些功能，比如拾取东西，放下东西，给材料上色。但是我在连接按钮（我在index.html中做的，当我用webgl运行我的项目时生成）和我的Unity代码时遇到了问题。webgl页面看起来像这样：my project
我已经用UnityLoader.instantiate尝试过了，但它对我不起作用，我得到了以下错误：UnityLoader - error
下面是我的Index.html中的脚本

<script>
      var container = document.querySelector("#unity-container");
      var canvas = document.querySelector("#unity-canvas");
      var loadingBar = document.querySelector("#unity-loading-bar");
      var progressBarFull = document.querySelector("#unity-progress-bar-full");
      var fullscreenButton = document.querySelector("#unity-fullscreen-button");
      var warningBanner = document.querySelector("#unity-warning");

      function unityShowBanner(msg, type) {
        function updateBannerVisibility() {
          warningBanner.style.display = warningBanner.children.length ? 'block' : 'none';
        }
        var div = document.createElement('div');
        div.innerHTML = msg;
        warningBanner.appendChild(div);
        if (type == 'error') div.style = 'background: red; padding: 10px;';
        else {
          if (type == 'warning') div.style = 'background: yellow; padding: 10px;';
          setTimeout(function() {
            warningBanner.removeChild(div);``
            updateBannerVisibility();
          }, 5000);
        }
        updateBannerVisibility();
      }

      var buildUrl = "Build";
      var loaderUrl = buildUrl + "/build.loader.js";
      var config = {
        dataUrl: buildUrl + "/build.data",
        frameworkUrl: buildUrl + "/build.framework.js",
        codeUrl: buildUrl + "/build.wasm",
        streamingAssetsUrl: "StreamingAssets",
        companyName: "DefaultCompany",
        productName: "warehouseOnline3D",
        productVersion: "0.1",
        showBanner: unityShowBanner,
      };

  
      if (/iPhone|iPad|iPod|Android/i.test(navigator.userAgent)) {
        // Mobile device style: fill the whole browser client area with the game canvas:

        var meta = document.createElement('meta');
        meta.name = 'viewport';
        meta.content = 'width=device-width, height=device-height, initial-scale=1.0, user-scalable=no, shrink-to-fit=yes';
        document.getElementsByTagName('head')[0].appendChild(meta);
        container.className = "unity-mobile";

        // To lower canvas resolution on mobile devices to gain some
        // performance, uncomment the following line:
        // config.devicePixelRatio = 1;

        canvas.style.width = window.innerWidth + 'px';
        canvas.style.height = window.innerHeight + 'px';

        unityShowBanner('WebGL builds are not supported on mobile devices.');
      } else {
        // Desktop style: Render the game canvas in a window that can be maximized to fullscreen:

        canvas.style.width = "960px";
        canvas.style.height = "600px";
      }

      loadingBar.style.display = "block";

      var script = document.createElement("script");
      script.src = loaderUrl;
      script.onload = () => {
        createUnityInstance(canvas, config, (progress) => {
          progressBarFull.style.width = 100 * progress + "%";
        }).then((unityInstance) => {
          loadingBar.style.display = "none";

          fullscreenButton.onclick = () => {
            unityInstance.SetFullscreen(1);
          };
        }).catch((message) => {
          alert(message);
        });
      };
      document.body.appendChild(script);
      
      var gameInstance = UnityLoader.instantiate("gameContainer", "Build/webgl.json");
      
      gameInstance.SendMessage("Sideloader", "test", "printed from webgl");  
    </script>

the function that should be called from the UnityLoader