//网页滚动事件,触发是指定元素的位置改变
<script type="text/javascript"> window.onscroll = function() { scrollItem(); } function scrollItem(){ //alert(document.body.scrollTop); if(navigator.userAgent.indexOf("Chrome")>0){ document.getElementById("notice_jqm").style.top=document.body.scrollTop+(document.documentElement.clientHeight-document.getElementById("notice_jqm").offsetHeight)/2+"px"; //alert(document.getElementById("winpop").style.top);document.getElementById("winpop").style.left=document.body.scrollLeft+(document.documentElement.clientWidth-document.getElementById("winpop").offsetWidth)/2+"px"; } else{ document.getElementById("notice_jqm").style.top=document.documentElement.scrollTop+(document.documentElement.clientHeight-document.getElementById("notice_jqm").offsetHeight)/2+"px"; //alert(document.getElementById("winpop").style.top);document.getElementById("winpop").style.left=document.documentElement.scrollLeft+(document.documentElement.clientWidth-document.getElementById("winpop").offsetWidth)/2+"px"; } } </script>