js实现分享到随页面滚动而滑动效果的方法

2019-11-20 12:43:42

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本文实例讲述了js实现分享到随页面滚动而滑动效果的方法。分享给大家供大家参考。具体如下：

页面向上向下滚动，分享到的模块随着滑动。

要点：

var scrtop =document.documentElement.scrollTop||document.body.scrollTop;
var height = document.documentElement.clientHeight||document.body.clientHeight;
var top = scrtop + (height - jb51.offsetHeight)/2;
top = parseInt(top);

获得页面垂直居中的位置

上代码：

<!DOCTYPE html><html><head><meta charset="gb2312" /><title>无标题文档</title><style>body{margin:0; padding:0; font:12px/1.5 arial; height:2000px;}#jb51{width:100px; height:200px; line-height:200px;text-align:center; border:1p solid #ccc;background:#f5f5f5; position:absolute; left:-100px; top:0;}#jb51_tit{position:absolute; right:-20px; top:60px;width:20px; height:60px; padding:10px 0;background:#06c; text-align:center;line-height:18px; color:#fff;}</style><script>window.onload = function(){ var jb51 = document.getElementById("jb51"); jb51.onmouseover = function(){ startrun(jb51,0,"left") } jb51.onmouseout = function(){ startrun(jb51,-100,"left") } window.onscroll = window.onresize = function(){ var scrtop=document.documentElement.scrollTop||document.body.scrollTop; var height=document.documentElement.clientHeight||document.body.clientHeight; var top = scrtop + (height - jb51.offsetHeight)/2; top = parseInt(top); startrun(jb51,top,"top") }}var timer = nullfunction startrun(obj,target,direction){ clearInterval(timer); timer = setInterval(function(){ var speed = 0; if(direction == "left"){  speed = (target-obj.offsetLeft)/8;  speed = speed>0?Math.ceil(speed):Math.floor(speed);  if(obj.offsetLeft == target){  clearInterval(timer);  }else{  obj.style.left = obj.offsetLeft + speed + "px";  } }  if(direction == "top"){  speed = (target-obj.offsetTop)/8;  speed = speed>0?Math.ceil(speed):Math.floor(speed);  if(obj.offsetTop == target){  clearInterval(timer);  }else{  obj.style.top = obj.offsetTop + speed + "px";  }  document.title = obj.offsetTop + ',' + target + ',' +speed; } },30)}</script></head><body><div id="jb51"> 分享到内容 <span id="jb51_tit">分享到</span></div></body></html>

希望本文所述对大家的javascript程序设计有所帮助。

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