調(diào)用例子1：
randomString()
輸出1：
JopzU1pJ7zu8E0d51JamTfE6IPLOGuvx
調(diào)用例子2：
randomString(16) //長度為16位
輸出2：
Ee2wH4nOUT1eSeLD
調(diào)用例子3：
randomString(16, INCLUDE_UPPERCASE) //只包含大寫字母
輸出3：
GFOBCQSQYFZXHZVD
調(diào)用例子4：
randomString(16, INCLUDE_UPPERCASE + INCLUDE_DIGIT) //只包含大寫字母和數(shù)字
輸出4：
16WPG8XHT8A0WC2Y
const?INCLUDE_UPPERCASE?=?1,INCLUDE_LOWERCASE?=?2,INCLUDE_DIGIT?=?4;function?randomString(len,?include)?{????len?=?len?||?32;include?=?include?||?7;var?$uppercase?=?"ABCDEFGHIJKLMNOPQRSTUVWXYZ";????var?$lowercase?=?$uppercase.toLowerCase();????var?$digit?=?"0123456789";????var?$chars?=?"";????if?(include?&?INCLUDE_UPPERCASE)????????$chars?+=?$uppercase;????if?(include?&?INCLUDE_LOWERCASE)????????$chars?+=?$lowercase;????if?(include?&?INCLUDE_DIGIT)????????$chars?+=?$digit;????var?maxPos?=?$chars.length;????var?str?=?"";????for?(var?i?=?0;?i?<?len;?i++)?{????????str?+=?$chars.charAt(Math.floor(Math.random()?*?maxPos));????}????return?str;}
