首先看一段ECMA中对Object.prototype.toString的解释:
1.If the this value is undefined, return "[object Undefined]".
2.If the this value is null, return "[object Null]".
3.Let O be the result of calling ToObject passing the this value as the argument.
4.Let class be the value of the [[Class]] internal property of O.
5.Return the String value that is the result o...阅读全文