/*
* -- 樣式說(shuō)明 --
* 最大優(yōu)先實(shí)現(xiàn)法，全局能實(shí)現(xiàn)不用區(qū)域，區(qū)域能實(shí)現(xiàn)不用模板，模板能實(shí)現(xiàn)不用界面，界面能實(shí)現(xiàn)不用標(biāo)簽
* g - 全局
* t - 區(qū)域
* m - 模板
* ui - 界面
* lb - 標(biāo)簽
* j - 腳本 只使用在有JS操作的樣式
*/
/*公共樣式*/
html, body, div, span, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, abbr, address, cite, code, del, dfn, em, img, ins, kbd, q, samp, small, strong, sub, sup, var, b, i, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, figure, footer, header, menu, nav, section, time, mark, audio, video, details, summary{ margin:0; padding:0;}
body{ font-family:Helvetica,Tahoma,Arial,sans-serif; color:#333; font-size:16px; background-color:#fff;}
input, select, textarea{ font-family:Helvetica,Tahoma,Arial,sans-serif; background:#fff; margin:0; padding:0; outline:none;}
textarea{ resize:none;}
img{ border:none;}
i, em{ font-style:normal;}
ul li{ list-style-type:none;}
a{ color:#06f; text-decoration:none;}
a:hover{ color:#06f; text-decoration:underline;}
/*全局樣式*/
.g-fl{ float:left;}
.g-fr{ float:right;}
.g-c{ clear:both;}

index.html：

<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1,maximum-scale=1, user-scalable=no">
<title>中間浮窗</title>
<link href="css/basic.css" rel="stylesheet">
<script src="js/jquery-1.10.1.min.js"></script>
</head>
<body>
<div style="height:10000px;"></div>
<style type="text/css">
/*建議先隱藏浮窗的樣式 display:none*/
.j-fixcenter{ height:120px; width:219px; background:#f60; display:none; position:fixed; }
</style>
<div id="fixCenter" class="j-fixcenter">
  <img src="img/fixCenter.jpg" width="219" height="120" usemap="#fixCenterMap">
  <!--繪制地圖，把圖片哪個(gè)位置要點(diǎn)擊的繪制出來(lái)-->
  <map name="fixCenterMap" id="fixCenterMap">
    <area shape="rect" coords="175,0,219,30" href="javascript:void();" id="closeFixCenter" />
    <area shape="rect" coords="0,30,219,94" href ="###2" />
    <area shape="rect" coords="0,94,219,120" href ="###3" />
  </map>
</div>
<script type="text/javascript">
$(function(){
  //調(diào)用浮窗方法
  fixCenter();
});
//當(dāng)調(diào)整瀏覽器窗口的大小時(shí)，發(fā)生 resize 事件
$(window).resize(function(){
  //重置浮窗定位
  fixCenterGetPosition();
});
function fixCenter(){
  //獲取浮窗定位
  fixCenterGetPosition();
  //獲取在浮窗的元素ID
  var fid = $("#fixCenter");
  //漸變顯示元素
  fid.fadeIn(600);
  //關(guān)閉按鈕的點(diǎn)擊事件
  $("#closeFixCenter").click(function(){
    //漸變隱藏元素，三秒后重新顯示
    fid.fadeOut(600).delay(3000).fadeIn(600);
  });
}
function fixCenterGetPosition(){
  var fid = $("#fixCenter");
  //獲取當(dāng)前窗口的高度
  var h = $(window).height();
  //獲取當(dāng)前窗口的寬度
  var w = $(window).width();
  //計(jì)算要定位左側(cè)距離
  var left = (w/2) - parseInt(fid.css("width")) / 2;
  //計(jì)算要定位上側(cè)距離
  var top = (h/2) - parseInt(fid.css("height")) / 2;
  //設(shè)置定位距離的樣式
  fid.css({"left":(left) + "px", "top": (top) + "px" });
}
</script>
</body>
</html>

效果圖：