https://purengom.com/2009/12/04/iphone%ec%9d%80-%eb%ac%b4%ec%84%a0-%ec%9d%b8%ed%84%b0%eb%84%b7%ec%9d%98-%ea%b2%bd%ea%b3%84%eb%a5%bc-%ed%97%88%eb%ac%b8%eb%8b%a4/