AbleOne

var getUsableHeight = function() {
	"use strict";
  
	// check if this page is within a app frame
	var isInAppMode = ("standalone" in navigator && navigator.standalone) || (window.chrome && window.top.chrome.app && window.top.chrome.app.isInstalled);
	
	var ua = navigator.userAgent;
	// memoized values
	var isIphone = ua.indexOf('iPhone') !== -1 || ua.indexOf('iPod') !== -1;