javascript and dom1

<script type="text/javascript">
            //数组
            var beatles=Array(4);
            var beatles=Array();
                console.log(beatles);//[]
            beatles[0]="John";
            beatles[1]="Paul";
            beatles[2]="George";
            beatles[3]="Ringo";
                console.log(beatles[3]);//Ringo
            var beatles=Array("John","Paul","George","Ringo");
                console.log(beatles.length);//4
            var beatles=["John","Paul","George","Ringo","Liuwei"];
                console.log(beatles[4]);//Liuwei
            var lennon=["John",1940,1943];
                console.log(lennon.length);//3
            var name="John";
            beatles[0]=name;
                console.log(beatles[0]);//John
            var names=["Ringo","John","George","Paul"];
            beatles[1]=names[2];
                console.log(beatles[1]);//George
            var lennon=["Ringo",1940,false];
            var beatles=[];
            beatles[0]=lennon;
                console.log(beatles[0]);//["Ringo",1940,false]
            var lennon=Array();
            lennon["name"]="John";//不建议用这种关联数组
            lennon["year"]=1943;
            lennon["living"]=false;
            console.log(lennon);//[]
                                //living  false
                                //name    "John"
                                //year    1943


        </script>