gistfile1.txt

propublica.views.stickyNav = propublica.View.extend({
  cssClass : "sticky_nav",

  render : function() {
    _.bindAll(this, "stick");
    this.jWindow   = $(window);
    this.jFooter   = $("footer");
    this.offsetTop = this.el.offset().top;
    this.elHeight  = this.el.height();
    this.jWindow.scroll(this.stick);
    this.bottomOffset = 250;
  },

  stick : function() {
    var windowTop = this.jWindow.scrollTop();
    var footerTop = this.jFooter.offset().top;
    if (windowTop > this.offsetTop && windowTop < footerTop - this.bottomOffset) {
      this.el
        .css("position", "fixed")
        .css("top", 5);
    } else if (windowTop > footerTop - this.bottomOffset) {
      this.el
      .css("position", "absolute")
      .css("top", footerTop - this.bottomOffset);
    } else {
      this.el
        .css("position", "relative");
    }
  }
});