A drainage system is provided for draining liquid accidentally spilled on a casing having a plurality of pushbuttons on a surface of the casing. An electronic apparatus may comprise a casing and a drainage system. The drainage system may be connected with the casing. The drainage system may include a liquid collecting basin, a drainage exit, and a liquid passageway. The liquid passageway may have a capillary surface and may lead the liquid from the liquid collecting basin to the drainage exit.