js- for in loop only one purpose, traverse the object, the number of circle by the number of control object properties

　　

obj = {var
 　　name: 'Suan',
 　　Sex: 'MALE',
 　　Age: 150,
 　　height: 185,
 　　characeter: to true
　　　　}
 for (var Key in obj) {
　　// the console.log (Key + '' + typeof (Key )) // return key string type
　　// console.log (obj.key -> obj [ 'key']); error writing key type string, given the underlying system does not converted into obj [ 'key'] In this case [ 'key'] is quantitative , will be considered to be inside the obj access key attribute
　　console.log (obj [key]) // key of type String
　　　　　　　　}