js cookie

<script>
 alert("cookie before= " + document.cookie);
 function addCookie(objName,objValue,objHours)
 {
  var str = objName + "=" + escape(objValue); 
  if(objHours > 0)
  {
   //为0时不设定过期时间，浏览器关闭时cookie自动消失 
   var date = new Date(); 
   var ms = objHours*3600*1000; 
   date.setTime(date.getTime() + ms); 
   str += "; expires=" + date.toGMTString(); 
  } 
  document.cookie = str; 
  alert("添加cookie成功"); 
 }
 addCookie("lang","zh_CN",100);
 alert("cookie after= " + document.cookie);
</script>