构造函数创建对象

<script type="text/javascript">
        function Car(make,model,year,color,passengers,convertible,mileage){
            this.make=make;
            this.model=model;
            this.year=year;
            this.color=color;
            this.passengers=passengers;
            this.convertible=convertible;        
            this.mileage=mileage;
            this.started=false;//将属性started初始化false
            this.start=function(){
                this.started=true;
            };
            this.stop=function(){
                this.started=false;
            };
            this.drive=function(){
                if (this.started) {
                    console.log(this.make+" " +this.model  +" does zoom zoom");
                } else {
                    alert("you are first");
                }
            };

        }
        var chevy1= new Car("chevy1","bel air1",1967,"red",2,false,20121);
        var chevy2= new Car("chevy2","bel air2",1967,"red",2,false,20122);
        var chevy3= new Car("chevy3","bel air3",1967,"red",2,false,20123);
        var chevy4= new Car("chevy4","bel air4",1967,"red",2,false,20124);
        var cars =  [chevy1,chevy2,chevy3,chevy4];
        for (var i = 0; i < cars.length; i++) {
            cars[i].start();
            cars[i].drive();
          
            cars[i].stop();
        }
    </script>

注意：构造函数命名是使用的是首字母大写，目的是为了区分普通函数   

　　　属性名和形参名不必相同，但通常相同 ，这是约定

　　　构造函数不用返回值return 本身会完成这项任务

　       先有构造函数  再有对象