简单实现js浮动框

<!-- 浮动窗口样式css begin -->
<style type="text/css">
#msg_win {
  border: 1px solid #A67901;
  background: #EAEAEA;
  width: 240px;
  position: absolute;
  right: 0;
  font-size: 12px;
  font-family: Arial;
  margin: 0px;
  display: none;
  overflow: hidden;
  z-index: 99;
}
#msg_win .icos {
  position: absolute;
  top: 2px;
  *top: 0px;
  right: 2px;
  z-index: 9;
}
.icos a {
  float: left;
  color: #833B02;
  margin: 1px;
  text-align: center;
  font-weight: bold;
  width: 14px;
  height: 22px;
  line-height: 22px;
  padding: 1px;
  text-decoration: none;
  font-family: webdings;
}
.icos a:hover {
  color: #fff;
}
#msg_title {
  background: #BBDEF6;
  border-bottom: 1px solid #A67901;
  border-top: 1px solid #FFF;
  border-left: 1px solid #FFF;
  color: #000;
  height: 25px;
  line-height: 25px;
  text-indent: 5px;
}
#msg_content {
  margin: 5px;
  margin-right: 0;
  width: 230px;
  height: 126px;
  overflow: hidden;
}
</style>
<!-- 浮动窗口样式css end -->

<!-- 浮动窗口js，必须要放置到最后 begin-->
<script type="text/javascript">
var Message={
  set: function() {//最小化与恢复状态切换
    var set=this.minbtn.status == 1?[0,1,'block',this.char[0],'最小化']:[1,0,'none',this.char[1],'展开'];
    this.minbtn.status=set[0];
    this.win.style.borderBottomWidth=set[1];
    this.content.style.display =set[2];
    this.minbtn.innerHTML =set[3]
    this.minbtn.title = set[4];
    this.win.style.top = this.getY().top;
  },
  close: function() {//关闭
    this.win.style.display = 'none';
    window.onscroll = null;
  },
  setOpacity: function(x) {//设置透明度
    var v = x >= 100 ? '': 'Alpha(opacity=' + x + ')';
    this.win.style.visibility = x<=0?'hidden':'visible';//IE有绝对或相对定位内容不随父透明度变化的bug
    this.win.style.filter = v;
    this.win.style.opacity = x / 100;
  },
  show: function() {//渐显
    clearInterval(this.timer2);
    var me = this,fx = this.fx(0, 100, 0.1),t = 0;
    this.timer2 = setInterval(function() {
      t = fx();
      me.setOpacity(t[0]);
      if (t[1] == 0) {clearInterval(me.timer2) }
    },10);
  },
  fx: function(a, b, c) {//缓冲计算
    var cMath = Math[(a - b) > 0 ? "floor": "ceil"],c = c || 0.1;
    return function() {return [a += cMath((b - a) * c), a - b]}
  },
  getY: function() {//计算移动坐标
    var d = document,b = document.body, e = document.documentElement;
    var s = Math.max(b.scrollTop, e.scrollTop);
    var h = /BackCompat/i.test(document.compatMode)?b.clientHeight:e.clientHeight;
    var h2 = this.win.offsetHeight;
    return {foot: s + h + h2 + 2+'px',top: s + h - h2 - 2+'px'}
  },
  moveTo: function(y) {//移动动画
    clearInterval(this.timer);
    var me = this,a = parseInt(this.win.style.top)||0;
    var fx = this.fx(a, parseInt(y));
    var t = 0 ;
    this.timer = setInterval(function() {
      t = fx();
      me.win.style.top = t[0]+'px';
      if (t[1] == 0) {
        clearInterval(me.timer);
        me.bind();
      }
    },10);
  },
  bind:function (){//绑定窗口滚动条与大小变化事件
    var me=this,st,rt;
    window.onscroll = function() {
      clearTimeout(st);
      clearTimeout(me.timer2);
      me.setOpacity(0);
      st = setTimeout(function() {
      me.win.style.top = me.getY().top;
      me.show();
      },600);
    };
    window.onresize = function (){
      clearTimeout(rt);
      rt = setTimeout(function() {me.win.style.top = me.getY().top},100);
    }
  },
  init: function() {//创建HTML
    function $(id) {return document.getElementById(id)};
    this.win=$('msg_win');
    var set={minbtn: 'msg_min',closebtn: 'msg_close',title: 'msg_title',content: 'msg_content'};
    for (var Id in set) {this[Id] = $(set[Id])};
    var me = this;
    this.minbtn.onclick = function() {me.set();this.blur()};
    this.closebtn.onclick = function() {me.close()};
    this.char=navigator.userAgent.toLowerCase().indexOf('firefox')+1?['_','::','×']:['0','2','r'];//FF不支持webdings字体
    this.minbtn.innerHTML=this.char[0];
    this.closebtn.innerHTML=this.char[2];
    setTimeout(function() {//初始化最先位置
      me.win.style.display = 'block';
      me.win.style.top = me.getY().foot;
      me.moveTo(me.getY().top);
    },0);
    return this;
  }
};
Message.init();
</script>
<!-- 浮动窗口js end-->

<!-- 浮动窗口html代码 begin -->
<hr>
<div id="msg_win" style="display: block; top: 490px; visibility: visible; opacity: 1;">
 <div class="icos">
  <a id="msg_min" title="最小化" href="javascript:void 0">_</a><a id="msg_close" title="关闭" href="javascript:void 0">×</a>
 </div>
 <div id="msg_title">设备运行情况--></div>
 <div id="msg_content" style="overflow: auto; height: 150px; width: 100%; white-space: nowrap">
  ${commonMsg.devRun } 
 </div>
</div>
<!-- 浮动窗口html代码 end -->