求鼠标点击页面随便地方显示出绝对定位的div代码

http://blog.csdn.net/xuexiaodong2009/article/details/6605417
参考下计算位置的方法
http://blog.csdn.net/xuexiaodong2009/article/details/6553292
<style type="text/css">.f{
cursor:pointer;
position:absolute;
border:1px solid #090;
background:#e9fde9 url(${pageContext.request.contextPath}/resource/images/frame/arr_tip_on.gif) 4px 6px no-repeat;
    padding:4px 3px 1px 14px;
    color:#444;
}
</style>
<script>
var oo = true;
function create(key,message){
  if(oo==true){
  oo=false
  var div =document.createElement("div");
  div.className="f";
  div.id="div";
  div.innerHTML="<font size='1'>"+message+"</font>";
  document.body.appendChild(div);
  var leftpos=0;
  var toppos=0;
  var obj=document.getElementByIdx(key);
  do {
   obj = obj.offsetParent; //得到上级位置元素对象
   leftpos += obj.offsetLeft;
   toppos += obj.offsetTop;
  }while(obj.tagName!="BODY");

  document.getElementByIdx("div").style.left=document.getElementByIdx(key).offsetLeft+leftpos;//
  document.getElementByIdx("div").style.top=document.getElementByIdx(key).offsetTop+document.getElementByIdx(key).offsetHeight+toppos;//位置：距离di为text的组件上边同样位置
  div.onmouseout=del;
  }}

  function del(e){
  e=e||event;
  var obj=e.relatedTarget||e.toElement;
  var div =document.getElementByIdx("div");
  if(div.contains(obj))return;
  document.body.removeChild(div);
  oo=true;
}</script>
<body onclick=ck()>
<script>
function ck()
{
弹出层代码;
}
</script>