js center advertising code on the left and right sides of the page_layout and layers

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Untitled Document</title> <style> #left{ width:200px;height:450px; position:absolute; left:0px; background:red; border:1px #000 solid} #right{width:200px;height:450px; position:absolute; right:0px; background:blue; border:1px #000 solid} #x,#y{ width:10px; height:10px;position:absolute;right:0px; top:0px;} </style> <div id="left"> <div id="x"> </div>x</div> <div id="right"> <div id="y"> </div>x</div>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

]<script> window.onload=window.onscroll=function() { var oLeft = document.getElementById("left"); var oRight = document.getElementById("right"); var scrollY=document.documentElement.scrollTop||document.body.scrollTop; var clientH = document.documentElement.clientHeight; var oCloseX =document.getElementById("x") var oCloseY =document.getElementById("y") oLeft.style.top=(clientH-oLeft.offsetHeight)/2+scrollY+"px"; oRight.style.top=(clientH-oRight.offsetHeight)/2+scrollY+"px"; oCloseX.onclick=function() { this.parentNode.parentNode.removeChild(this.parentNode); } } </script>