1Array.prototype.contains = function(value) {
 2    return this.indexOf(value) > -1;
 3}
 4
 5function fadeIn(elementId) {
 6    var element = document.getElementById(elementId);
 7    // Avoid single JavaScript rounds (http://stackoverflow.com/q/24148403)
 8    element.offsetWidth = element.offsetWidth;
 9    element.classList.add("fadein");
10}