This is a follow on from the favorite simple tooltip graph used as an example in the book D3 Tips and Tricks.
It impliments a more complex example than the simple version and is designed to illustrate additional things you can do with the technique. It should be taken in context with the text of the book which can be downloaded for free from Leanpub.
forked from d3noob's block: Favorite tooltip (complex version)
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js