SessionStorage and LocalStorage allows to save key/value pairs in a web browser. The value must be a string, and save js objects is not trivial.
var user = {
Could you not 'stringify' your object...then use sessionStorage.setItem() to store that string representation of your object...then when you need it sessionStorage.getItem() and then use $.parseJSON() to get it back out?
sessionStorage.setItem()
sessionStorage.getItem()
$.parseJSON()
Working example http://jsfiddle.net/pKXMa/