详解ECMAScript typeof用法

> var bundefined> typeof(b)'undefined'> typeof e'undefined'>

> var a = new Object()undefined> typeof a'object'> var b = new String("str")undefined> typeof b'object'> var c = new Boolean(false)undefined> typeof c'object'>> var d = []undefined> typeof d'object'>> var e = {}undefined> typeof e'object'>

> var a = 98undefined> typeof a'number'> var b = 'aaa'undefined> typeof b'string'> var c = trueundefined> typeof c'boolean'>