The following is a simple cheat to keep your zoo generating cash and not timing out when when you have to leave your desk or you ALT TAB to a different browser. To do the cheat you must use Firefox and install an add-on called ReloadEvery which allows you to set any browser page to auto-refresh after a specified time. Just right click anywhere inside the Zoo World browser page, select 'Reload Every' and toggle the 'Enable' option.