window.open弹出窗口居中

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');
}