document.body ,window.screen javascript对象属性取值意义

<SCRIPT LANGUAGE="JavaScript">
<!--

var s = "";
    s += " 网页可见区域宽："+ document.body.clientWidth;
    s += " 网页可见区域高："+ document.body.clientHeight;
    s += " 网页可见区域宽："+ document.body.offsetWidth + " (包括边线和滚动条的宽)";
    s += " 网页可见区域高："+ document.body.offsetHeight + " (包括边线的宽)";
    s += " 网页正文全文宽："+ document.body.scrollWidth;
    s += " 网页正文全文高："+ document.body.scrollHeight;
    s += " 网页被卷去的高(ff)："+ document.body.scrollTop;
    s += " 网页被卷去的高(ie)："+ document.documentElement.scrollTop;
    s += " 网页被卷去的左："+ document.body.scrollLeft;
    s += " 网页正文部分上："+ window.screenTop;
    s += " 网页正文部分左："+ window.screenLeft;
    s += " 屏幕分辨率的高："+ window.screen.height;
    s += " 屏幕分辨率的宽："+ window.screen.width;
    s += " 屏幕可用工作区高度："+ window.screen.availHeight;
    s += " 屏幕可用工作区宽度："+ window.screen.availWidth;
    s += " 你的屏幕设置是 "+ window.screen.colorDepth +" 位彩色";
    s += " 你的屏幕设置 "+ window.screen.deviceXDPI +" 像素/英寸";
    alert (s);

//-->