a.ScrollTop calculation;
b. Positioning value calculation of scroll element;
c. Scroll cycle setting;
The code is as follows:
css part:
/*测试用的高度*/
body{ height:3000px;}
div,ul,li,body{margin:0; padding:0;}
/*position:absolute;用于元素的定位*/
#roll{width:50px; height:100px; background:#99CC00; position:absolute;}Html code:
<body> <div id="roll"></div> </body>
JS code:
var roll=document.getElementById('roll'),
initX=0,
initY,
compY,
sp=15,
//可调整时间间隔，步进值不宜过大，不然IE下有点闪屏；
timeGap=5,
doc=document.documentElement,
docBody=document.body;
compY=initY=200;
roll.style.right=initX+"px";
;(function(){
var curScrollTop=(doc.scrollTop||docBody.scrollTop||0)-(doc.clientTop||docBody.clientTop||0);
//每次comP的值都不一样；直到roll.style.top===doc.scrollTop+initY；
compY+=(curScrollTop+initY-compY)/sp;
roll.style.top=Math.ceil(compY)+"px";
setTimeout(arguments.callee,timeGap);
})();For more js web page side scrolling advertising effects, please pay attention to the PHP Chinese website!
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
