// A function that takes three values, then returns one of them based on
// the best guess at which platform the current browser is running on.
// The most appropriate value for the current OS is the return value of this function.
function chooseBasedOnOS(windowsValue, macValue, otherValue) {
	var ua = navigator.userAgent.toLowerCase();
	if (ua.indexOf('windows') > 0) {
	  return windowsValue;
	} else if (ua.indexOf('mac') > 0) {
	  return macValue;
	} else {
	  return otherValue;
	}
}