javascript call方法

<script>            function Class1()            {                this.name ="clsss1";                this.showName =function()                    {                        alert(this.name);                    }            }            function Class2()            {                this.name = "calss2";            }            var c1 = new Class1();            var c2 = new Class2();            c1.showName.call(c2);</script>