8点击每个图片弹出对话框

<img src="../logo1.png" alt="" width="120px">
        <img src="../logo2.png" alt="" width="120px">
        <img src="../logo3.png" alt="" width="120px">
        <script type="text/javascript">
            var imgg = document.getElementsByTagName("img");
                for(var i=0;i<imgg.length;i++){
                    imgg[i].onclick=function(){
                        alert("被点了");
                    };
                }    
        </script>