var a={};Object.defineProperty(a,"z",{value:10});var obj=new Object(a);Object.defineProperty(obj,"z",{value:100});//報Uncaught TypeError: Cannot redefine property: zObject.getOwnPropertyDescriptor(obj,"z");//configurable:?false?enumerable:?false?value:?10?writable:?falsevar a={z:1};? ? ? ?Object.defineProperty(a,"z",{value:10});? ? ? ?var obj=new Object(a);? ? ? ?Object.defineProperty(obj,"z",{value:100});?Object.getOwnPropertyDescriptor(obj,"z");//configurable:?true?enumerable:?true?value:?100?writable:?true為什么第一種寫法會報Uncaught TypeError: Cannot redefine property: z這個故障,是因為第一種情況下z屬性的幾個標(biāo)簽都為false的原因嗎？如果是，為什么為false就不能重新設(shè)呢？
以下兩種方法有什么不同
慕姐8259394
2017-09-05 22:52:59
