封装cookie的添加，删除，查询方法

gistfile1.txt

CookieUtil=｛
    addCookie:function(key,value,options){
        var str=key+"="+escape(value);
        if(options.expires){
           var curr=new Date();   //options.expires的单位是小时
           curr.setTime(curr.getTime()+options.expires*3600*1000);
           options.expires=curr.toGMTString();
        }
        for(var k in options){   //有可能指定了cookie的path，cookie的domain
           str+=";"+k+"="+options[k];
        }
        document.cookie=str;
    },
    queryCookie:function(key){
      var cookies=document.cookie;
     //获得浏览器端存储的cookie,格式是key=value;key=value;key=value
      cookies+=";";
      var start=cookies.indexOf(key);
      if(start<=-1){ return null; }  //说明不存在该cookie
      var end=cookies.indexOf(";",start);
      var value=cookies.slice(start+key.length+1,end);
      return unescape(value);
    },
    deleteCookie:function(key){
      var value=CookieUtil.queryCookie(key);
      if(value===null){return false;}
      CookieUtil.addCookie(key,value,{expires:0});//把过期时间设置为0，浏览器会马上自动帮我们删除cookie
    }
｝