/**
* Return the height of the screen in pixels. Meant to be called if isMobileUser()
* returns true. See also getScreensize().
*
* @return height of the screen in pixels
*/
function getScreenHeight()
{
$screen = getScreenSize();
return isset($screen['height']) ? $screen['height'] : null;
}
function getUserId()
{
return md5(getUserIpAddr() . getBrowserAndPlatform() . getScreenSize());
}