//写cookiesfunction setCookie(c_name, value, expiredays){     var exdate=new Date();    exdate.setDate(exdate.getDate() + expiredays);    document.cookie=c_name+ "=" + escape(value) + ((expiredays==null) ? "" : ";expires="+exdate.toGMTString());   }function setCookie(name,value){
				var Days = 30;
				var exp = new Date();
				exp.setTime(exp.getTime() + Days*24*60*60*1000);
				let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)  //设置为一级域名
				document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString()+";domain="+hostname+";path=/";
			}
  //读取cookiesfunction getCookie(name){ var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");   if(arr=document.cookie.match(reg))    return (arr[2]); else  return null;}//删除cookiesfunction delCookie(name){ var exp = new Date(); exp.setTime(exp.getTime() - 1); var cval=getCookie(name); if(cval!=null)  document.cookie= name + "="+cval+";expires="+exp.toGMTString();}function delCookie(name){var exp = new Date();
            var name = "access_token";
            exp.setTime(exp.getTime() - 1);
            var cval=getCookie(name);
            if(cval!=null){
                let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)
                document.cookie= name + "=‘‘;expires="+exp.toGMTString()+";domain="+hostname+";path=/";
            }
//使用示例setCookie(‘username‘,‘Darren‘,30) alert(getCookie("username"));原文:http://www.cnblogs.com/qdlhj/p/8012842.html