//获取指定名称的cookie的值

 function getCookie(objName) {

     var arrStr = document.cookie.split("; ");

     for (var i = 0; i < arrStr.length; i++) {

         var temp = arrStr[i].split("=");

         if (temp[0] == objName) return unescape(temp[1]);

     }

 }

 //添加cookie

 function addCookie(objName, objValue, objHours) {

     var str = objName + "=" + escape(objValue);

     if (objHours > 0) {                               //为时不设定过期时间，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;

 }

 //删除cookie

 function delCookie(name)

 {

     document.cookie = name + "=;expires=" + (new Date(0)).toGMTString();

 }