JS windows.open打开窗口并居中

function openWin() {             var url='Add.aspx';                             //转向网页的地址;             var name='add';                            //网页名称，可为空;             var iWidth=720;                          //弹出窗口的宽度;             var iHeight=600;                         //弹出窗口的高度;             //获得窗口的垂直位置             var iTop = (window.screen.availHeight - 30 - iHeight) / 2;             //获得窗口的水平位置             var iLeft = (window.screen.availWidth - 10 - iWidth) / 2;             window.open(url, name, 'height=' + iHeight + ',,innerHeight=' + iHeight + ',width=' + iWidth + ',innerWidth=' + iWidth + ',top=' + iTop + ',left=' + iLeft + ',status=no,toolbar=no,menubar=no,location=no,resizable=no,scrollbars=0,titlebar=no');            // window.open("http://p.qiao.baidu.com/cps/chat?siteId=10377321&userId=19759389", "newWindows", 'height=100,width=400,top=0,left=0,toolbar=no,menubar=no,scrollbars=no, resizable=no,location=no, status=no');         }