ion.display(6);

    // Navigation loaded
    book.loaded.navigation.then(function(toc){
      // console.log(toc);
    });

    var next = document.getElementById("next");
    next.addEventListener("click", function(){
      rendition.next();
    }, false);

    var prev = document.getElementById("prev");
    prev.addEventListener("click", function(){
      rendition.prev();
    }, false);

    var keyListener = function(e){

      // Left Key
      if ((e.keyCode || e.which) == 37) {
        rendition.pre