js打开新窗口并且居中显示

function openwindow(url,name,iWidth,iHeight)
{
 var url;                            //转向网页的地址;
 var name;                           //网页名称，可为空;
 var iWidth;                         //弹出窗口的宽度;
 var iHeight;                        //弹出窗口的高度;
 var iTop = (window.screen.availHeight-30-iHeight)/2;       //获得窗口的垂直位置;
 var iLeft = (window.screen.availWidth-10-iWidth)/2;        //获得窗口的水平位置;
 window.open(url,name,'height='+iHeight+',,innerHeight='+iHeight+',width='+iWidth+',innerWidth='+iWidth+',top='+iTop+',left='+iLeft+',toolbar=no,menubar=no,scrollbars=auto,resizeable=no,location=no,status=no');
 
}