@evidentpoint/readium-css/css/demo/demo-script.js

A set of reference stylesheets for EPUB Reading Systems

document.addEventListener("DOMContentLoaded", function(event) {
  var frame = document.getElementById("page");
  var scrollLeft = function() {
    var gap = parseInt(window.getComputedStyle(frame.contentWindow.document.documentElement).getPropertyValue("column-gap"));
    frame.contentWindow.scrollTo(frame.contentWindow.scrollX - frame.contentWindow.innerWidth - gap, 0);
  };

  var scrollRight = function() {
    var gap = parseInt(window.getComputedStyle(frame.contentWindow.document.documentElement).getPropertyValue("column-gap"));
    frame.contentWindow.scrollTo(frame.contentWindow.scrollX + frame.contentWindow.innerWidth + gap, 0);
  };

  document.body.addEventListener('click', function(e) {
    e.preventDefault();
    if (e.clientX > (window.innerWidth / 2)) {
      scrollRight();
    } else {
      scrollLeft();
    }
  });
  document.body.addEventListener('keydown', function(e) {
    if (e.keyCode == "39") {
      scrollRight();
    } else if (e.keyCode == "37") {
      scrollLeft();
    }
  });
})