In addition to touch events, modern mobile applications generally require more complex input events, such as device
rotation. Thus mobile platforms are equipped many sensors nowadays. For instances, geolocation is obtained from GPS
sensor, and gyro sensor can be used to check gravity. The XHTML5 described above can only manipulate touch events
and keyboard events from mobile platforms. This limitation is because that browser has not enough permission to access
hardware devices. Therefore, remove device access (RDA) is developed to compensate this shortfall.