It seems like you have opened this file by double-clicking on it. In order to test your build in a browser you need to load this file from a web server. You can either upload this file and the rest of the files from a Defold HTML5 bundle to a web hosting service OR host them using a local web server on your home network.
The example uses a script to tint (color) sprites in a couple of different ways. The tint is a fragment constant on the sprite material and it is used in the sprite.fp fragment shader program to modify the color sampled from the texture.
It is important to keep in mind that each tinted sprite generates a new draw call since a modified tint value will break the built in draw call batching in Defold.
If you want to play with these examples, you can get the project on Github.
Do you want to see more examples? Why not write a few yourself and submit a pull request? We love contributions.GITHUB