js获得浏览器宽高，奇怪的问题

function GetInfo()

{

var s = "";

    s += "\r\n网页可见区域宽："+ document.body.clientWidth;

    s += "\r\n网页可见区域高："+ document.body.clientHeight;

    s += "\r\n网页可见区域宽："+ document.body.offsetWidth + " (包括边线和滚动条的宽)";

    s += "\r\n网页可见区域高："+ document.body.offsetHeight + " (包括边线的宽)";

    s += "\r\n网页正文全文宽："+ document.body.scrollWidth;

    s += "\r\n网页正文全文高："+ document.body.scrollHeight;

    s += "\r\n网页被卷去的高(ff)："+ document.body.scrollTop;

    s += "\r\n网页被卷去的高(ie)："+ document.documentElement.scrollTop;

    s += "\r\n网页被卷去的左："+ document.body.scrollLeft;

    s += "\r\n网页正文部分上："+ window.screenTop;

    s += "\r\n网页正文部分左："+ window.screenLeft;

    s += "\r\n屏幕分辨率的高："+ window.screen.height;

    s += "\r\n屏幕分辨率的宽："+ window.screen.width;

    s += "\r\n屏幕可用工作区高度："+ window.screen.availHeight;

    s += "\r\n屏幕可用工作区宽度："+ window.screen.availWidth;

    s += "\r\n你的屏幕设置是 "+ window.screen.colorDepth +" 位彩色";

    s += "\r\n你的屏幕设置 "+ window.screen.deviceXDPI +" 像素/英寸";

    alert (s);

}