Version: 2018.2 (switch to 2018.1 or 2017.4)
WebGL: Deploying compressed builds
WebGL Graphics
Other Versions

Debugging and trouble shooting WebGL builds

Unity 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
content cannot currently be debugged in Visual Studio, which can make it difficult to find out what exactly is going wrong with your content. Here are some tips on how to get information out of your buildThe process of compiling your project into a format that is ready to run on a specific platform or platforms. More info
See in Glossary
.

The browser’s JavaScript console

Unity WebGL does not have access to your file system, so it will not write a log file like other platforms. However, it will write all logging information which would normally go to the log file (such as Debug.Log, Console.WriteLine or Unity’s internal logging) to the browser’s JavaScript console.

  • In Firefox, you can open the JavaScript console by pressing Ctrl-Shift-K on Windows or Command-Option-K on a Mac
  • In Chrome, you can open the JavaScript console by pressing Ctrl-Shift-J on Windows or Command-Option-J on a Mac.
  • In Safari, you can open the JavaScript console by enabling the Develop menu in the Advanced tabs in Preferences, and then pressing Command-Option-C.
  • In Microsoft Edge or Internet Explorer, you can open the JavaScript console by pressing F12.

Development builds

For debugging purposes, you may typically want to make a development buildA development build includes debug symbols and enables the Profiler. More info
See in Glossary
in Unity (the Development Build checkbox in the Build Settings window). Development builds allow you to connect the profilerA window that helps you to optimize your game. It shows how much time is spent in the various areas of your game. For example, it can report the percentage of time spent rendering, animating or in your game logic. More info
See in Glossary
, and they will not be minified, so the emitted JavaScript code will still contain human-readable (though C++-mangled) function names. These can be used by the browser to display stack traces when you run into a browser error, or when you throw an exception and exception support is disabled, or when using Debug.LogError. Unlike the managed stack traces which you can get when enabling Full exception support (see below), these stack traces will have mangled names, and contain not only managed code, but also the internal UnityEngine code.

Exception support

WebGL has different levels of exception support (See the page on Building for WebGL). By default, Unity WebGL will only support explicitly thrown exceptions. You can enable Full exception support which will then emit additional checks in the IL2CPPA Unity-developed scripting back-end which you can use as an alternative to Mono when building projects for some platforms. More info
See in Glossary
generated code to catch access to null references and out-of-bounds array elements in your managed code. These additional checks will significantly impact performance and increase code size and load times, so this mode is only recommended for debugging.

Full exception support will also emit function names to generate stack traces for your managed code. So you will see stack traces in the console for uncaught exceptions and for Debug.Log statements, and you can get a stack trace string using System.Environment.Stacktrace.


  • 2018–03–19  Page amended with limited editorial review

  • MonoDevelop replaced by Visual Studio from 2018.1

Did you find this page useful? Please give it a rating:

WebGL: Deploying compressed builds
WebGL Graphics