json - How do I parse variables from URL in javascript?

I'm creating a client side application where the experience runs linearly with data carried over from the last step. I've decided that the best way to do this is by serializing my JSON data and including it into the url.

I'm aware of using example.com?key=value&key2=value2 to pass data server side in a GET request, but how do I parse it client side?

Bonus: is there a library you use to do this? Links to docs will be appreciated.