javascript获取浏览器的宽度和高度

<script language="JavaScript" type="text/JavaScript">
<!--
        function displayScreenSize()
        {
            var bodyWidth           =document.body.clientWidth;               //网页可见区域宽
            var bodyHeight          =document.body.clientHeight;              //网页可见区域高
            var bodyWidthWithBorder =document.body.offsetWidth;      //网页可见区域宽(包括边线的宽)
            var bodyHeightWithBorder=document.body.offsetHeight;     //网页可见区域高(包括边线的宽)
            var bodyWidthWithScroll =document.body.scrollWidth;         //网页正文全文宽
            var bodyHeightWithScroll=document.body.scrollHeight;        //网页正文全文高 
            var bodyTopHeight       =document.body.scrollTop;               //网页被卷去的上边距
            var bodyLeftWidth       =document.body.scrollLeft;               //网页被卷去的左边距