Python in the Browser examples.
Here's a big table of technologies (not created by me). It's a little out of date but there's a lot of useful information there.
Here's an article I wrote about Python in the Browser for pythontips.com.
Anvil is a project that uses Python in the Browser as a basis for a web app development platform. It does much more than just client-side Python, it solves a lot of other pain points in web development - for example it allows you to call functions on the server from the client.