Refactor examples

[mhchia]

What’s wrong?

We have examples for browser and nodejs. They actually have common code snippets and should be able to be combined into one example, which makes it easier to maintain the code.

How to fix it?

We can combine two examples into one, and people can just run different commands in the same example project. For instance, npm run browser for browser and npm run node for node

[0xkf]

I would like to give it a shot,

[mhchia]

Great, thanks! Is the issue clear enough, or something you'd like to clarify? Let me know if you encounter any issues