function openWindow(){
        var mywin=confirm("确认要打开么");
        if(mywin==true)

     {
            var i=prompt("打开哪个网址？","http://www.imooc.com");
            if(i!=null){
                window.open("http://www.imooc.com","_blank","width=400,height=500,menubar=no,toolbar=no");
            }
           
        }
        else{
            alert("亲，打不开哟");
        }
    }