This tutorial is going to cover building a game in Unity for Web GL. First you need to go to File->Build Settings. Select Web GL from the platform options. In the bottom right of the window you will need to click Switch Platform. This will take a couple of minutes to compile.
Next, you need to go to Player Settings to fix an error related to the Color Space. In Player Settings go down to the Other Settings drop down. Change the Color Space to Gamma. This may take a couple of minutes to update.
Back in the Build Settings it is now ready to build. Click the Build button and select a folder to save it to like WebGL Demo. This may take a couple of minutes to build.
When this is done it will open the location of the files that were created. These are the files that you could host on the web so that your game can be played from your website.
Good Luck Adventurer!