js学习cookie封装之添加

添加cookie
function setCookie(name,value,expires,domain){
          var cookie = name + '=' + value;
          //有失效日期时
          if(expires){
                 cookie +=';expires' +expires
          }

           //有域名限制时
          if(domain){
                 cookie += ';domain' + domain
         }      
      
          //写入cookie
          document.cookie = cookie;    
}