/*1.
2.
3.prototype */
var person = function(){
var age = 22;
function showName(){
console.log(this.name)
};
this.show = function(){
console.log(this.name);
showName();
}
}
person.prototype.setname = function(str){
name = str;
}
var p1 = new person();
p1.setname("");
p1.show();
console.log(p1.age);//undefinedWhy is the this.name under the this.show method undefiend, and the this.name under the showName method Dabao?