I struggled for weeks on a skill that uses session attributes because there's no clear, simple, detailed documentation about session attributes available for javascript devs---at least, not in the MANY articles, books and sites I've been scouring since late May. With invaluable help from some other devs I finally got session attributes working in my skill and, compulsive documenter that I am, I've written the guide I wish had been available when I first got started working with session attributes in javascript. I hope this can save some other javascript devs the weeks of wasted time, effort and frustration I endured.
http://lovemyecho.com/wp-content/uploads/2015/07/SessionAttributesInJavascript.pdf