浮动广告网页里面浮动广告怎么做啊

网页里面浮动广告怎么做啊

<script> var speed=40;//滚动速度 var AdLayer1="dd1";//左侧div的ID var AdLayer2="dd2";//右侧div的ID function initEcAd() { document.getElementById(AdLayer1).style.posTop = -200; document.getElementById(AdLayer1).style.visibility = 'visible' document.getElementById(AdLayer2).style.posTop = -200; document.getElementById(AdLayer2).style.visibility = 'visible' MoveLeftLayer(AdLayer1); MoveRightLayer(AdLayer2); } function MoveLeftLayer(layerName) { var x = 5;//左侧广告maring-left值 var y = 100;// 左侧广告距离页首高度 var diff = (document.body.scrollTop + y - document.getElementById(AdLayer1).style.posTop)*.40; var y = document.body.scrollTop + y - diff; eval("document.getElementById('" + layerName +"').style.posTop = parseInt(y)"); eval("document.getElementById('" + layerName + "').style.posLeft = x"); setTimeout("MoveLeftLayer(AdLayer1);", speed); } function MoveRightLayer(layerName) { var x = 5; var y = 100;// 右侧广告距离页首高度 var diff = (document.body.scrollTop + y - document.getElementById(AdLayer2).style.posTop)*.40; var y = document.body.scrollTop + y - diff; eval("document.getElementById('" + layerName + "').style.posTop = y"); eval("document.getElementById('" + layerName + "').style.posRight = x"); setTimeout("MoveRightLayer(AdLayer2);", speed); } </script> <body onload="initEcAd()"> <div id=dd1 style="position: absolute;visibility:hidden;z-index:1; border:1px solid red; height:200px; width:100px"></div> <div id=dd2 style="position: absolute;visibility:hidden;z-index:1; border:1px solid red; height:200px; width:100px"></div> <div style="height:2000px"></div> </body> <script> </script>