in-view.js

/**
 * Check if element fully visible.
 * @param {jQuery} $el.
 * @returns {boolean} Is visible or not.
 */
isScrolledIntoView: function ($el) {
  var $window = $(window);
  var docViewTop = $window.scrollTop();
  var docViewBottom = docViewTop + $window.height();
  var elemTop = $el.offset().top;
  var elemBottom = elemTop + $el.height();
  
  return (elemBottom <= docViewBottom) && (elemTop >= docViewTop);
}