// JavaScript Document
function openwindow( url, winName, width, height) 
{
xposition=0; yposition=0;

if ((parseInt(navigator.appVersion) >= 4 ))
{
xposition = (screen.width - width) / 2;
yposition = (screen.height - height) / 2;
}
theproperty= "width=" + width + ","+ "height=" + height + "," + "location=0," + "menubar=0,"+ "resizable=1,"+ "scrollbars=0,"+ "status=0," + "titlebar=0,"+ "toolbar=0,"+ "hotkeys=0,"+ "screenx=" + xposition + "," //仅适用于Netscape
+ "screeny=" + yposition + "," //仅适用于Netscape
+ "left=" + xposition + "," //IE
+ "top=" + yposition; //IE 
window.open( url,winName,theproperty );
}