I want to JavaScript project(including html, css) to improve my skills. What is the best way?
I have the book "Professional JavaScript for Web Developers". And I am currently do problems at http://projecteuler.net/.However it primarily focus on the algorithm and math skills.

My final goal is that I can write a chrome extension in the future. My near target to master DOM etc.

I just think is there a homework/project something like therefore I can exercise it.