SOURCE

$(function() {
  $("#ewm-close").click(function() {
    $(this).parent().hide();
  });

  //相对固定悬浮窗位置
  function scrollx(p) {
    var d = document,
    dd = d.documentElement,
    db = d.body,
    w = window,
    o = d.getElementById(p.id),
    ie6 = /msie 6/i.test(navigator.userAgent),
    style,
    timer;
    if (o) {
      cssPub = ";position:" + (p.f && !ie6 ? 'fixed': 'absolute') + ";" + (p.t != undefined ? 'top:' + p.t + 'px;': 'bottom:0;');
      if (p.r != undefined && p.l == undefined) {
        o.style.cssText += cssPub + ('right:' + p.r + 'px;');
      } else {
        o.style.cssText += cssPub + ('margin-left:' + p.l + 'px;');
      }
      if (p.f && ie6) {
        cssTop = ';top:expression(documentElement.scrollTop +' + (p.t == undefined ? dd.clientHeight - o.offsetHeight: p.t) + '+ "px" );';
        cssRight = ';right:expression(documentElement.scrollright + ' + (p.r == undefined ? dd.clientWidth - o.offsetWidth: p.r) + ' + "px")';
        if (p.r != undefined && p.l == undefined) {
          o.style.cssText += cssRight + cssTop;
        } else {
          o.style.cssText += cssTop;
        }
        dd.style.cssText += ';background-image: url(about:blank);background-attachment:fixed;';
      } else {
        if (!p.f) {
          w.onresize = w.onscroll = function() {
            clearInterval(timer);
            timer = setInterval(function() {
              //双选择为了修复chrome 下xhtml解析时dd.scrollTop为 0 
              var st = (dd.scrollTop || db.scrollTop),
              c;
              c = st - o.offsetTop + (p.t != undefined ? p.t: (w.innerHeight || dd.clientHeight) - o.offsetHeight);
              if (c != 0) {
                o.style.top = o.offsetTop + Math.ceil(Math.abs(c) / 10) * (c < 0 ? -1 : 1) + 'px';
              } else {
                clearInterval(timer);
              }
            },
            10)
          }
        }
      }
    }
  }

  if (screen.height > 800) { //粗暴地处理分辨率对浮窗的影响
    scrollx({
      id: 'jdSmall',
      r: 0,
      t: screen.height - 640,
      f: 1
    });
  } else if (screen.height > 720) {
    scrollx({
      id: 'jdSmall',
      r: 0,
      t: screen.height - 545,
      f: 1
    });
  } else {
    scrollx({
      id: 'jdSmall',
      r: 0,
      t: screen.height - 460,
      f: 1
    });
  }

});

<div id="jdSmall" style="position: absolute; right: 0px;top :screen.height-450;  z-index: 9999;">
  <a href="#">
    <img class="img_piaochuang1" src="">
  </a>
  <a href="javascript:void(0)" id="ewm-close" style="width:27px; height:21px; position:absolute; right:0; top:0; background:url()) no-repeat right 0;">
  </a>
</div>