判断数组类型为 Array
Object.prototype.toString.call(obj) == '[object Array]'
判断对象类型为 Object
Object.prototype.toString.call(obj) == '[object Object]'
判断对象类型为 Number
Object.prototype.toString.call(obj) == '[object Number]'
Object.prototype.toString.call(obj) == '[object Array]'
Object.prototype.toString.call(obj) == '[object Object]'
Object.prototype.toString.call(obj) == '[object Number]'