Cookie = {
  

  "write":function(name, value, expires) {
  

  if(expires == null) {
  

  var d = new Date();
  

  d.setTime(d.getTime() + 24 * 60 * 60 * 1000);
  

  expires = d.toGMTString();
  

  }
  

  document.cookie = name + "=" + escape(value) + ";expires=" + expires;
  

  },
  

  "read":function(name) {
  

  var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
  

  if(arr!=null) {
  

  return unescape(arr[2]);
  

  }
  

  return null;
  

  },
  

  "remove":function(name) {
  

  var value = Cookie.read(name);
  

  if(value!=null) {
  

  document.cookie = name + "=" + value + ";expires=Fri, 02-Jan-1970 00:00:00 GMT";
  

  }
  

  }
  

  }
  

  

  Cookie.write("name", "dewen.org");//测试cookie，默认设置一天
  

  

  //记录打开的地址数量
  

  var host = location.host;
  

  var pageCount = parseInt(Cookie.read(host));
  

  Cookie.write(host, isNaN(pageCount) ? 1 : (pageCount + 1));
  

  

  window.onunload = function() {
  

  //判断打开的地址数量
  

  var pageCount = parseInt(Cookie.read(host));
  

  pageCount = isNaN(pageCount) ? 0 : (--pageCount);
  

  if(pageCount == 0) {
  

  //处理cookie失效
  

  Cookie.remove(location.host);
  

  Cookie.remove("name");//清除cookie
  

  alert(Cookie.read("name"));
  

  }else {
  

  Cookie.write(locaion.host, pageCount);
  

  }
  

  }