Build your WebGL application

To create a build for WebGL, go to File > Build Settings from Unity’s main menu. In the Platform list, select WebGL and then click Switch Platform.

When you have configured the Build Settings, choose one the following options:

• Build: Builds your application into a Player.
• Build and Run: Builds your application in a Player, and opens that Player on your target platform.

The Unity build system for WebGLA JavaScript API that renders 2D and 3D graphics in a web browser. The Unity WebGL build option allows Unity to publish content as JavaScript programs which use HTML5 technologies and the WebGL rendering API to run Unity content in a web browser. More info
See in Glossary supports the following settings:

For changing the settings for Asset Import Overrides, see Build Settings.

Build Folder

The Build folder contains the following files ([ExampleBuild] represents the name of the target build folder).

If you enable a Compression Method for your build, Unity identifies the extension that corresponds with the compression method and adds this extension to the names of the files inside the Build subfolder. If you enable Decompression Fallback, Unity appends the extension .unityweb to the build file names. Otherwise, Unity appends the extension .gz for the Gzip compression method, or .br for the Brotli compression method. For more information, see WebGL: Compressed builds and server configuration.

If you enable Name Files As Hashes in the Player Settings, Unity uses the hash of the file content instead of the default filename. This applies to each file in the build folder. This option allows you to upload updated versions of the game builds into the same folder on the server, and only upload the files which have changed between build iterations.

Note: Opening a Player directly from the file system might not work in some browsers. This is due to security restrictions applied to local file URLs.

Deep Profiling Support

Enable the Deep Profiling Support setting to make the Unity Profiler profile every function call in your application. For more information see the documentation on Deep Profiling.

Enable Exceptions

Open Publishing Settings to access Enable Exceptions. Enable Exceptions allows you to specify how unexpected code behavior (also known as errors) is handled at run time. It has these options:

• None: Select this if you don’t need any exception support. This gives the best performance and smallest builds. With this option, any exception thrown causes your content to stop with an error in that setting.
• Explicitly Thrown Exceptions Only (default): Select this to capture exceptions which are explicitly specified from a throw statement in your scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
  See in Glossary and to also ensure finally blocks are called. Note that selecting this option makes the generated JavaScript code from your scripts longer and slower; This might only be an issue if scripts are the main bottleneck in your project.
• Full Without Stacktrace: Select this option to capture: * Exceptions which are explicitly specified from throw statements in your scripts (the same as in the Explicitly Thrown Exceptions Only option)
  • Null References
  • Out of Bounds Array accesses
• Full With Stacktrace: This option is similar to the option above but it also captures Stack traces. Unity generates these exceptions by embedding checks for them in the code, so this option decreases performance and increases browser memory usage. Only use this for debugging, and always test in a 64-bit browser.

Data Caching

To access Data Caching, go to Publishing Setings via File > Build Settings > Player Settings > WebGL. This enables the browser to cache the main data files into the IndexedDB database.

Using the default browser HTTP cache does not guarantee that the browser caches a particular response. This is because the browser HTTP cache has limited space, and the browser might not be able to cache files that are too large.

To improve your loading speed, IndexedDB allows you to cache files above the browser limit. When you cache more files, you increase the chance that downloaded content is available on the user’s machine during the next run of the build.

Data Caching only caches the .data files in the IndexedDB cache for HTTP responses. To cache AssetBundles, you need to enable Data Caching and override unityInstance.Module.cacheControl(). To do this, make sure Module.cacheControl(url) returns must-revalidate for the requested AssetBundle URL. For example, you can override the unityInstance.Module.cacheControl() function in the fulfillment callback of the Promise that createUnityInstance() returns. For further information on createUnityInstance() see WebGL: Compressed builds and server configuration.

Texture Compression

The texture compression setting in WebGL lets you create builds that target platforms based on the texture compression formats they support. The texture compression format value you set here has priority over the Player settings texture compression format value. To run your game on both desktop and mobile browsers with compressed textures, you might want to create two builds: * Targeting desktop browsers with DXT set as the texture compression format * Targeting mobile browsers with ASTC set as the texture compression format

Create builds for desktop and mobile browsers from a script

You can run a build for both desktop browsers and mobile browsers with the corresponding texture compression formats simultaneously using a script. For example:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Diagnostics;
using System.IO;
using UnityEditor.Build.Reporting;

public class comboBuild
{
    //This creates a menu item to trigger the dual builds https://docs.unity3d.com/ScriptReference/MenuItem.html 

    [MenuItem("Game Build Menu/Dual Build")]
    public static void BuildGame()
    {
      //This builds the player twice: a build with desktop-specific texture settings (WebGL_Build) as well as mobile-specific texture settings (WebGL_Mobile), and combines the necessary files into one directory (WebGL_Build)
      
      string dualBuildPath    = "WebGLBuilds";
      string desktopBuildName = "WebGL_Build";
      string mobileBuildName  = "WebGL_Mobile";

      string desktopPath = Path.Combine(dualBuildPath, desktopBuildName);
      string mobilePath  = Path.Combine(dualBuildPath, mobileBuildName);
      string[] scenes = new string[] {"Assets/scene.unity"};

      EditorUserBuildSettings.webGLBuildSubtarget = WebGLTextureSubtarget.DXT;
      BuildPipeline.BuildPlayer(scenes, desktopPath, BuildTarget.WebGL, BuildOptions.Development); 

      EditorUserBuildSettings.webGLBuildSubtarget = WebGLTextureSubtarget.ASTC;
      BuildPipeline.BuildPlayer(scenes,  mobilePath, BuildTarget.WebGL, BuildOptions.Development); 

      // Copy the mobile.data file to the desktop build directory to consolidate them both
      FileUtil.CopyFileOrDirectory(Path.Combine(mobilePath, "Build", mobileBuildName + ".data"), Path.Combine(desktopPath, "Build", mobileBuildName + ".data"));
    }  
}

You can modify the WebGL template’s index.html file to select the appropriate data file if there’s support for the texture compression format extension:

// choose the data file based on whether there's support for the ASTC texture compression format
      var dataFile = "/{{{ DATA_FILENAME }}}";                                  
      var c = document.createElement("canvas");                                 
      var gl = c.getContext("webgl");                                      
      var gl2 = c.getContext("webgl2");                                    
      if ((gl && gl.getExtension('WEBGL_compressed_texture_astc')) || (gl2 &&   
              gl2.getExtension('WEBGL_compressed_texutre_astc'))) {             
        dataFile =  "/WebGL_Mobile.data";                                       
      }                                                                         

      var buildUrl = "Build";
      var loaderUrl = buildUrl + "/{{{ LOADER_FILENAME }}}";                    
      var config = {                                                            
        dataUrl: buildUrl + dataFile,                                           
        frameworkUrl: buildUrl + "/{{{ FRAMEWORK_FILENAME }}}",                 
#if USE_WASM                                                                    
        codeUrl: buildUrl + "/{{{ CODE_FILENAME }}}",                           
#endif                                                                          
#if MEMORY_FILENAME                                                             
        memoryUrl: buildUrl + "/{{{ MEMORY_FILENAME }}}",                       
#endif
#if SYMBOLS_FILENAME                                                            
        symbolsUrl: buildUrl + "/{{{ SYMBOLS_FILENAME }}}",                     
#endif                                                                          
        streamingAssetsUrl: "StreamingAssets",                                
        companyName: {{{ JSON.stringify(COMPANY_NAME) }}},
        productName: {{{ JSON.stringify(PRODUCT_NAME) }}},
      productVersion: {{{ JSON.stringify(PRODUCT_VERSION) }}},                
        showBanner: unityShowBanner,                                            
     };  

• Removed asm.js linker target in Unity 2019.1
• Build file updates and Data Caching added in Unity 2020.1