构造函数模式

    function student(props){
        this.name=props.name || ‘匿名‘;//默认是匿名
        this.grade=props.grade || 1;
    }
    student.prototype.hello=function(){
        console.log(‘hello ‘+this.name);
    }
    function createStudent(props){
        return new student(props||{})
    }
    var xiaoming=createStudent({
        name:‘xiaoming‘
    });
    xiaoming.hello();//hello xiaoming

    function animal(name,age,grade){
        this.name=name;
        this.age=age;
        this.grade=grade;
    }
    animal.prototype.hello=function(){
        console.log(‘hello ‘+this.name);
    }
    var chicken=new animal(‘chicken‘,3,12);
    chicken.hello();//hello chicken