è¿ä¸¤ä¸ªå¯ä»¥è¯´é¤äºå符串é¿åº¦ç¸åï¼æ²¡æä»»ä½å ±åç¹ï¼
jsåºå大å°åï¼æ以ä»ä»¬ä¸¤ä¸ªä¸æ¯ä¸åäºã
String æ¯æé å½æ°ï¼stringæ¯åéçä¸ä¸ªç±»å
typeof String æ¯functionï¼ typeof string æ¯ string
String('xxx') è¿åçæ¯ä¸ä¸ªå符串ãStringæå±æ§åæ¹æ³ï¼èstring没æã