[browser] Change default boot config to dotnet.boot.js (#113374)

Author: maraf

src/mono/browser/build/BrowserWasmApp.targets

@@ -130,6 +130,9 @@
       <_WasmPThreadPoolInitialSize Condition="'$(_WasmPThreadPoolInitialSize)' == ''">-1</_WasmPThreadPoolInitialSize>
       <_WasmPThreadPoolUnusedSize Condition="'$(_WasmPThreadPoolUnusedSize)' == ''">-1</_WasmPThreadPoolUnusedSize>
       <_WasmIsPublishing Condition="'$(_WasmIsPublishing)' == '' and '$(_IsPublishing)' != ''">$(_IsPublishing)</_WasmIsPublishing>
+      
+      <_WasmAppBuilderBootConfigFileName>$(WasmBootConfigFileName)</_WasmAppBuilderBootConfigFileName>
+      <_WasmAppBuilderBootConfigFileName Condition="'$(_WasmAppBuilderBootConfigFileName)' == ''">dotnet.boot.js</_WasmAppBuilderBootConfigFileName>
     </PropertyGroup>
 
     <ItemGroup>
@@ -141,6 +144,7 @@
     <RemoveDir Directories="$(WasmAppDir)" />
     <WasmAppBuilder
       AppDir="$(WasmAppDir)"
+      ConfigFileName="$(_WasmAppBuilderBootConfigFileName)"
       Assemblies="@(_WasmAssembliesInternal)"
       MainAssemblyName="$(WasmMainAssemblyFileName)"
       HostConfigs="@(HostConfig)"

src/mono/browser/runtime/dotnet.d.ts

@@ -58,11 +58,11 @@ declare type TypedArray = Int8Array | Uint8Array | Uint8ClampedArray | Int16Arra
 interface DotnetHostBuilder {
     /**
      * @param config default values for the runtime configuration. It will be merged with the default values.
-     * Note that if you provide resources and don't provide custom configSrc URL, the blazor.boot.json will be downloaded and applied by default.
+     * Note that if you provide resources and don't provide custom configSrc URL, the dotnet.boot.js will be downloaded and applied by default.
      */
     withConfig(config: MonoConfig): DotnetHostBuilder;
     /**
-     * @param configSrc URL to the configuration file. ./blazor.boot.json is a default config file location.
+     * @param configSrc URL to the configuration file. ./dotnet.boot.js is a default config file location.
      */
     withConfigSrc(configSrc: string): DotnetHostBuilder;
     /**
@@ -376,7 +376,7 @@ type SingleAssetBehaviors =
  */
  | "js-module-native"
 /**
- * Typically blazor.boot.json
+ * Typically dotnet.boot.js
  */
  | "manifest"
 /**

src/mono/browser/runtime/loader/config.ts

@@ -240,10 +240,7 @@ export async function mono_wasm_load_config (module: DotnetModuleInternal): Prom
     try {
         if (!module.configSrc && (!loaderHelpers.config || Object.keys(loaderHelpers.config).length === 0 || (!loaderHelpers.config.assets && !loaderHelpers.config.resources))) {
             // if config file location nor assets are provided
-            // Temporal way for tests to opt-in for using boot.js
-            module.configSrc = (globalThis as any)["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"]
-                ?? globalThis.window?.document?.documentElement?.getAttribute("data-dotnet_internal_boot_config_src")
-                ?? "blazor.boot.json";
+            module.configSrc = "dotnet.boot.js";
         }
 
         configFilePath = module.configSrc;
@@ -336,6 +333,16 @@ async function loadBootConfig (module: DotnetModuleInternal): Promise<void> {
         loaderHelpers.config.applicationEnvironment = "Production";
     }
 
+    if (loaderHelpers.config.debugLevel !== 0 && document.querySelector("script[src*='aspnetcore-browser-refresh']")) {
+        loaderHelpers.config.environmentVariables = loaderHelpers.config.environmentVariables || {};
+        if (!loaderHelpers.config.environmentVariables["DOTNET_MODIFIABLE_ASSEMBLIES"]) {
+            loaderHelpers.config.environmentVariables["DOTNET_MODIFIABLE_ASSEMBLIES"] = "debug";
+        }
+        if (!loaderHelpers.config.environmentVariables["__ASPNETCORE_BROWSER_TOOLS"]) {
+            loaderHelpers.config.environmentVariables["__ASPNETCORE_BROWSER_TOOLS"] = "true";
+        }
+    }
+
     function fetchBootConfig (url: string): Promise<Response> {
         return loaderHelpers.fetch_like(url, {
             method: "GET",

src/mono/browser/runtime/types/index.ts

@@ -6,11 +6,11 @@ import type { EmscriptenModule, NativePointer } from "./emscripten";
 export interface DotnetHostBuilder {
     /**
      * @param config default values for the runtime configuration. It will be merged with the default values.
-     * Note that if you provide resources and don't provide custom configSrc URL, the blazor.boot.json will be downloaded and applied by default.
+     * Note that if you provide resources and don't provide custom configSrc URL, the dotnet.boot.js will be downloaded and applied by default.
      */
     withConfig(config: MonoConfig): DotnetHostBuilder;
     /**
-     * @param configSrc URL to the configuration file. ./blazor.boot.json is a default config file location.
+     * @param configSrc URL to the configuration file. ./dotnet.boot.js is a default config file location.
      */
     withConfigSrc(configSrc: string): DotnetHostBuilder;
     /**
@@ -256,7 +256,7 @@ export interface LoadingResource {
     response: Promise<Response>;
 }
 
-// Types of assets that can be in the _framework/blazor.boot.json file (taken from /src/tasks/WasmAppBuilder/WasmAppBuilder.cs)
+// Types of assets that can be in the _framework/dotnet.boot.js file (taken from /src/tasks/WasmAppBuilder/WasmAppBuilder.cs)
 export interface AssetEntry {
     /**
      * the name of the asset, including extension.
@@ -335,7 +335,7 @@ export type SingleAssetBehaviors =
      */
     | "js-module-native"
     /**
-     * Typically blazor.boot.json
+     * Typically dotnet.boot.js
      */
     | "manifest"
     /**

src/mono/browser/test-main.js

@@ -117,7 +117,7 @@ function initRunArgs(runArgs) {
     runArgs.enableGC = runArgs.enableGC === undefined ? true : runArgs.enableGC;
     runArgs.diagnosticTracing = runArgs.diagnosticTracing === undefined ? false : runArgs.diagnosticTracing;
     runArgs.debugging = runArgs.debugging === undefined ? false : runArgs.debugging;
-    runArgs.configSrc = runArgs.configSrc === undefined ? './_framework/blazor.boot.json' : runArgs.configSrc;
+    runArgs.configSrc = runArgs.configSrc === undefined ? './_framework/dotnet.boot.js' : runArgs.configSrc;
     // default'ing to true for tests, unless debugging
     runArgs.forwardConsole = runArgs.forwardConsole === undefined ? !runArgs.debugging : runArgs.forwardConsole;
     runArgs.interpreterPgo = runArgs.interpreterPgo === undefined ? false : runArgs.interpreterPgo;

src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets

@@ -171,6 +171,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_TargetingNET90OrLater>false</_TargetingNET90OrLater>
       <_TargetingNET80OrLater Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals('$(TargetFrameworkVersion)', '8.0'))">true</_TargetingNET80OrLater>
       <_TargetingNET90OrLater Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals('$(TargetFrameworkVersion)', '9.0'))">true</_TargetingNET90OrLater>
+      <_TargetingNET100OrLater Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals('$(TargetFrameworkVersion)', '10.0'))">true</_TargetingNET100OrLater>
 
       <_BlazorEnableTimeZoneSupport>$(BlazorEnableTimeZoneSupport)</_BlazorEnableTimeZoneSupport>
       <_BlazorEnableTimeZoneSupport Condition="'$(_BlazorEnableTimeZoneSupport)' == ''">true</_BlazorEnableTimeZoneSupport>
@@ -193,7 +194,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_WasmFingerprintDotnetJs>$(WasmFingerprintDotnetJs)</_WasmFingerprintDotnetJs>
       <_WasmFingerprintDotnetJs Condition="'$(_WasmFingerprintDotnetJs)' == ''">$(WriteImportMapToHtml)</_WasmFingerprintDotnetJs>
       <_WasmFingerprintDotnetJs Condition="'$(_WasmFingerprintDotnetJs)' == ''">false</_WasmFingerprintDotnetJs>
+      <_WasmFingerprintBootConfig>$(WasmFingerprintBootConfig)</_WasmFingerprintBootConfig>
+      <_WasmFingerprintBootConfig Condition="'$(_WasmFingerprintBootConfig)' == ''">$(WriteImportMapToHtml)</_WasmFingerprintBootConfig>
+      <_WasmFingerprintBootConfig Condition="'$(_WasmFingerprintBootConfig)' == ''">false</_WasmFingerprintBootConfig>
       <_WasmBootConfigFileName>$(WasmBootConfigFileName)</_WasmBootConfigFileName>
+      <_WasmBootConfigFileName Condition="'$(_WasmBootConfigFileName)' == '' and '$(_TargetingNET100OrLater)' == 'true'">dotnet.boot.js</_WasmBootConfigFileName>
       <_WasmBootConfigFileName Condition="'$(_WasmBootConfigFileName)' == ''">blazor.boot.json</_WasmBootConfigFileName>
       <_WasmPublishBootConfigFileName>publish.$(_WasmBootConfigFileName)</_WasmPublishBootConfigFileName>
 
@@ -316,9 +321,9 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target Name="_AddWasmStaticWebAssets" DependsOnTargets="$(AddWasmStaticWebAssetsDependsOn)">
     <ItemGroup>
       <StaticWebAsset Include="@(WasmStaticWebAsset)" />
-      <StaticWebAsset Include="@(_BuildWasmBootJsonStaticWebAsset)" />
+      <StaticWebAsset Include="@(_WasmBuildBootConfigStaticWebAsset)" />
       <StaticWebAssetEndpoint Include="@(WasmStaticWebAssetEndpoint)" />
-      <StaticWebAssetEndpoint Include="@(_BuildWasmBootJsonStaticWebAssetEndpoint)" />
+      <StaticWebAssetEndpoint Include="@(_WasmBuildBootConfigStaticWebAssetEndpoint)" />
     </ItemGroup>
   </Target>
 
@@ -391,18 +396,18 @@ Copyright (c) .NET Foundation. All rights reserved.
       <FileWrites Include="$(_WasmBuildBootJsonPath)" />
     </ItemGroup>
 
-    <PropertyGroup>
-      <_WasmBuildBootJsonPath>$(IntermediateOutputPath)$(_WasmBootConfigFileName)</_WasmBuildBootJsonPath>
-    </PropertyGroup>
-
     <ItemGroup>
-      <_BuildWasmBootJson
+      <_WasmBuildBootConfigCandidate
         Include="$(_WasmBuildBootJsonPath)"
         RelativePath="_framework/$(_WasmBootConfigFileName)" />
+
+      <_WasmBuildBootConfigFingerprintPatterns Include="WasmBootConfigFiles" Pattern="*%(_WasmBuildBootConfigCandidate.Extension)" Expression="#[.{fingerprint}]!" />
     </ItemGroup>
 
     <DefineStaticWebAssets
-      CandidateAssets="@(_BuildWasmBootJson)"
+      CandidateAssets="@(_WasmBuildBootConfigCandidate)"
+      FingerprintCandidates="$(_WasmFingerprintBootConfig)"
+      FingerprintPatterns="@(_WasmBuildBootConfigFingerprintPatterns)"
       SourceId="$(PackageId)"
       SourceType="Computed"
       AssetKind="Build"
@@ -414,15 +419,15 @@ Copyright (c) .NET Foundation. All rights reserved.
       ContentRoot="$(OutDir)wwwroot"
       BasePath="$(StaticWebAssetBasePath)"
     >
-      <Output TaskParameter="Assets" ItemName="_BuildWasmBootJsonStaticWebAsset" />
+      <Output TaskParameter="Assets" ItemName="_WasmBuildBootConfigStaticWebAsset" />
     </DefineStaticWebAssets>
 
     <DefineStaticWebAssetEndpoints
-      CandidateAssets="@(_BuildWasmBootJsonStaticWebAsset)"
+      CandidateAssets="@(_WasmBuildBootConfigStaticWebAsset)"
       ExistingEndpoints="@(StaticWebAssetEndpoint)"
       ContentTypeMappings="@(StaticWebAssetContentTypeMapping)"
     >
-      <Output TaskParameter="Endpoints" ItemName="_BuildWasmBootJsonStaticWebAssetEndpoint" />
+      <Output TaskParameter="Endpoints" ItemName="_WasmBuildBootConfigStaticWebAssetEndpoint" />
     </DefineStaticWebAssetEndpoints>
 
   </Target>
@@ -587,14 +592,19 @@ Copyright (c) .NET Foundation. All rights reserved.
   </Target>
 
   <Target Name="_AddPublishWasmBootJsonToStaticWebAssets" DependsOnTargets="GeneratePublishWasmBootJson">
+
     <ItemGroup>
-      <_PublishWasmBootJson
+      <_WasmPublishBootConfigCandidate
         Include="$(IntermediateOutputPath)$(_WasmPublishBootConfigFileName)"
         RelativePath="_framework/$(_WasmBootConfigFileName)" />
+
+      <_WasmPublishBootConfigFingerprintPatterns Include="WasmBootConfigFiles" Pattern="*%(_WasmPublishBootConfigCandidate.Extension)" Expression="#[.{fingerprint}]!" />
     </ItemGroup>
 
     <DefineStaticWebAssets
-      CandidateAssets="@(_PublishWasmBootJson)"
+      CandidateAssets="@(_WasmPublishBootConfigCandidate)"
+      FingerprintCandidates="$(_WasmFingerprintBootConfig)"
+      FingerprintPatterns="@(_WasmPublishBootConfigFingerprintPatterns)"
       SourceId="$(PackageId)"
       SourceType="Computed"
       AssetKind="Publish"
@@ -607,11 +617,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       BasePath="$(StaticWebAssetBasePath)"
     >
       <Output TaskParameter="Assets" ItemName="StaticWebAsset" />
-      <Output TaskParameter="Assets" ItemName="_PublishWasmBootJsonStaticWebAsset" />
+      <Output TaskParameter="Assets" ItemName="_WasmPublishBootConfigStaticWebAsset" />
     </DefineStaticWebAssets>
 
     <DefineStaticWebAssetEndpoints
-      CandidateAssets="@(_PublishWasmBootJsonStaticWebAsset)"
+      CandidateAssets="@(_WasmPublishBootConfigStaticWebAsset)"
       ExistingEndpoints="@(StaticWebAssetEndpoint)"
       ContentTypeMappings="@(StaticWebAssetContentTypeMapping)"
     >

src/mono/sample/wasm/browser-advanced/index.html

@@ -10,7 +10,7 @@
   <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'wasm-unsafe-eval';" />
   <script type='module' src="./main.js"></script>
   <script type='module' src="./dotnet.js"></script>
-  <link rel="preload" href="./blazor.boot.json" as="fetch" crossorigin="use-credentials">
+  <link rel="preload" href="./dotnet.boot.js" as="fetch" crossorigin="use-credentials">
   <link rel="prefetch" href="./dotnet.native.js" as="fetch" crossorigin="anonymous">
   <link rel="prefetch" href="./dotnet.runtime.js" as="fetch" crossorigin="anonymous">
   <link rel="prefetch" href="./advanced-sample.lib.module.js" as="fetch" crossorigin="anonymous">

src/mono/sample/wasm/browser-advanced/main.js

@@ -46,7 +46,7 @@ try {
             }
         })
         .withModuleConfig({
-            configSrc: "./blazor.boot.json",
+            configSrc: "./dotnet.boot.js",
             onConfigLoaded: (config) => {
                 // This is called during emscripten `dotnet.wasm` instantiation, after we fetched config.
                 console.log('user code Module.onConfigLoaded');

src/mono/sample/wasm/browser-bench/appstart-frame.html

@@ -9,7 +9,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <script type="module" src="./frame-main.js"></script>
   <script type='module' src="./dotnet.js"></script>
-  <link rel="preload" href="./blazor.boot.json" as="fetch" crossorigin="use-credentials">
+  <link rel="preload" href="./dotnet.boot.js" as="fetch" crossorigin="use-credentials">
   <link rel="prefetch" href="./dotnet.native.js" as="fetch" crossorigin="anonymous">
   <link rel="prefetch" href="./dotnet.runtime.js" as="fetch" crossorigin="anonymous">
 </head>

src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTestsBase.cs

@@ -80,28 +80,11 @@ public ProjectInfo CreateWasmTemplateProject(
             .ExecuteWithCapturedOutput($"new {template.ToString().ToLower()} {extraArgs}")
             .EnsureSuccessful();
 
-        UpdateBootJsInHtmlFiles();
-
         string projectFilePath = Path.Combine(_projectDir, $"{projectName}.csproj");
         UpdateProjectFile(projectFilePath, runAnalyzers, extraProperties, extraItems, insertAtEnd);
         return new ProjectInfo(projectName, projectFilePath, logPath, nugetDir);
     }
 
-    protected void UpdateBootJsInHtmlFiles()
-    {
-        foreach (var filePath in Directory.EnumerateFiles(_projectDir, "*.html", SearchOption.AllDirectories))
-        {
-            UpdateBootJsInHtmlFile(filePath);
-        }
-    }
-
-    protected void UpdateBootJsInHtmlFile(string filePath)
-    {
-        string fileContent = File.ReadAllText(filePath);
-        fileContent = StringReplaceWithAssert(fileContent, "<head>", "<head><script>window['__DOTNET_INTERNAL_BOOT_CONFIG_SRC'] = 'dotnet.boot.js';</script>");
-        File.WriteAllText(filePath, fileContent);
-    }
-
     protected ProjectInfo CopyTestAsset(
         Configuration config,
         bool aot,
@@ -180,7 +163,11 @@ public virtual (string projectDir, string buildOutput) BuildProject(
 
         buildOptions.ExtraBuildEnvironmentVariables["TreatPreviousAsCurrent"] = "false";
 
-        buildOptions = buildOptions with { ExtraMSBuildArgs = $"{buildOptions.ExtraMSBuildArgs} -p:WasmBootConfigFileName={buildOptions.BootConfigFileName}" };
+        if (buildOptions.BootConfigFileName != "dotnet.boot.js")
+        {
+            // Omit implicit default
+            buildOptions = buildOptions with { ExtraMSBuildArgs = $"{buildOptions.ExtraMSBuildArgs} -p:WasmBootConfigFileName={buildOptions.BootConfigFileName}" };
+        }
 
         (CommandResult res, string logFilePath) = BuildProjectWithoutAssert(configuration, info.ProjectName, buildOptions);
 

src/mono/wasm/Wasm.Build.Tests/WasmRunOutOfAppBundleTests.cs

@@ -38,8 +38,6 @@ public async void RunOutOfAppBundle(Configuration config, bool aot)
             File.WriteAllText(indexHtmlPath, html);
         }
 
-        UpdateBootJsInHtmlFile(indexHtmlPath);
-
         RunResult result = await RunForPublishWithWebServer(new BrowserRunOptions(
                 config,
                 TestScenario: "DotnetRun",

src/mono/wasm/build/WasmApp.Common.targets

@@ -92,8 +92,8 @@
       - @(WasmFilesToIncludeInFileSystem) - Files to include in the vfs
       - @(WasmNativeAsset)        - Native files to be added to `NativeAssets` in the bundle.
 
-      - @(WasmEnvironmentVariable)        - add environment variables `_framework/blazor.boot.json`
-      - @(WasmExtraConfig)        - json elements to add to `_framework/blazor.boot.json`
+      - @(WasmEnvironmentVariable)        - adds environment variables to `_framework/dotnet.boot.js`
+      - @(WasmExtraConfig)        - json elements to add to `_framework/dotnet.boot.js`
                                     Eg. <WasmExtraConfig Include="xxx" Value="true" />
 
                                     - Value attribute can have a number, bool, quoted string, or json string

src/mono/wasm/features.md

@@ -166,7 +166,7 @@ Note: You can replace the location of `AppBundle` directory by  `<WasmAppDir>../
 - `dotnet.js` - is the main entrypoint with the [JavaScript API](#JavaScript-API). It will load the rest of the runtime.
 - `dotnet.native.js` - is posix emulation layer provided by the [Emscripten](https://github.com/emscripten-core/emscripten) project
 - `dotnet.runtime.js` - is integration of the dotnet with the browser
-- `blazor.boot.json` - contains list of all other assets and their integrity hash and also various configuration flags.
+- `dotnet.boot.js` - contains list of all other assets and their integrity hash and also various configuration flags.
 - `dotnet.native.wasm` - is the compiled binary of the dotnet (Mono) runtime.
 - `System.Private.CoreLib.*` - is NET assembly with the core implementation of dotnet runtime and class library
 - `*.wasm` - are .NET assemblies stored in `WebCIL` format (for better compatibility with firewalls and virus scanners).
@@ -202,7 +202,7 @@ Adding too many files into prefetch could be counterproductive.
 Please benchmark your startup performance on real target devices and with realistic network conditions.
 
 ```html
-<link rel="preload" href="./_framework/blazor.boot.json" as="fetch" crossorigin="use-credentials">
+<link rel="preload" href="./_framework/dotnet.boot.js" as="fetch" crossorigin="use-credentials">
 <link rel="prefetch" href="./_framework/dotnet.native.js" as="fetch" crossorigin="anonymous">
 <link rel="prefetch" href="./_framework/dotnet.runtime.js" as="fetch" crossorigin="anonymous">
 ```

src/mono/wasm/testassets/BlazorBasicTestApp/App/wwwroot/index.html

@@ -26,7 +26,6 @@
         <a href="." class="reload">Reload</a>
         <span class="dismiss">🗙</span>
     </div>
-    <script>window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] = "dotnet.boot.js";</script>
     <script src="_framework/blazor.webassembly.js"></script>
 </body>
 

src/mono/wasm/testassets/LibraryMode/wwwroot/index.html

@@ -7,7 +7,6 @@
   <title>tmp</title>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <script>window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] = "dotnet.boot.js";</script>
   <script type='module' src="./main.js"></script>
 </head>
 

src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/index.html

@@ -7,7 +7,6 @@
   <title>WasmLazyLoading</title>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <script>window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] = "dotnet.boot.js";</script>
   <script type='module' src="./main.js"></script>
   <script type='module' src="./profiler.js"></script>
 </head>

src/mono/wasm/testassets/WasmOnAspNetCore/BlazorClient/wwwroot/index.html

@@ -16,7 +16,6 @@
         <a href="" class="reload">Reload</a>
         <a class="dismiss">🗙</a>
     </div>
-    <script>window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] = "dotnet.boot.js";</script>
     <script src="_framework/blazor.webassembly.js"></script>
 </body>
 

src/mono/wasm/testassets/WasmOnAspNetCore/WasmBrowserClient/wwwroot/index.html

@@ -7,7 +7,6 @@
   <title>WasmBrowser</title>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <script>window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] = "dotnet.boot.js";</script>
   <script type='module' src="./main.js"></script>
 </head>