How do I keep data without using sessions
If you don't need your data server side, you could use cookies, using user_cookie_save. Or store your variables in window.localStorage (it's HTML5, see here for browser support) in your own javascript code/behavior, like :

function storePersistentValue() {

  //Check whether local storage is available or not

  if (window.localStorage) {

    window.localStorage.MyKey = "HTML 5 features";

  }

}

function getPersistentValue() {

  //Check whether local storage is available or not

  if (window.localStorage) {

    var text = window.localStorage.MyKey;

  }

}