js获取屏幕尺寸、网页可见区域、网页正文、屏幕分辨率

<script>
document.write("屏幕尺寸："+screen.width+"*"+screen.height)
</script>
<br/>---------------------------------------------------------------<br/>
<script>
function  centerWindow(url,w,h){
l=(screen.width-w)/2
t=(screen.height-h)/2
window.open(url,'','left='+l+',top='+t+',width='+w+',height='+h)
}
</script>
<input  type=button  onclick="centerWindow('about:blank',200,200)" value="打开一个200*200的窗口">
<br/>---------------------------------------------------------------<br/>
<SCRIPT  LANGUAGE="JavaScript">
var    s  ="网页可见区域宽："+  document.body.clientWidth;
s+="<br/>网页可见区域高："+  document.body.clientHeight;
s  +=  "<br/>网页正文全文宽："+  document.body.scrollWidth;
s  +=  "<br/>网页正文全文高："+  document.body.scrollHeight;
s  +=  "<br/>网页正文部分上："+  window.screenTop;
s  +=  "<br/>网页正文部分左："+  window.screenLeft;
s  +=  "<br/>屏幕分辨率的高："+  window.screen.height;
s  +=  "<br/>屏幕分辨率的宽："+  window.screen.width;
s  +="<br/>屏幕可用工作区高度："+  window.screen.availHeight;
s  +="<br/>屏幕可用工作区宽度："+  window.screen.availWidth;
document.write(s);
</SCRIPT>
<br/>---------------------------------------------------------------<br/>
<SCRIPT  LANGUAGE="JavaScript">
<!--  Begin
function  redirectPage()  {
/*var  url640x480  =  "http://www.looooking.cn/";**记得改相应的页面*/
var  url800x600  =  "index_800x600.asp";
var  url1024x768  =  "index_1024x768.asp";
/*if  ((screen.width  ==  640)  &&  (screen.height  ==  480))
window.location.href=  url640x480;*/
 if  (screen.width  <=  800)
window.location.href=  url800x600;
else  if  ((screen.width  >=  1024))
window.location.href=  url1024x768;
}
//  End  -->
</script>
<input  type=button  onclick="redirectPage()" value="不同的屏幕显示不同的页面">