function getCookieVal (offset) { 
    var endstr = document.cookie.indexOf (";", offset); 
    if (endstr == -1) endstr = document.cookie.length; 
    return unescape(document.cookie.substring(offset, endstr)); 
} 
                         
function getCookie (name) {
         var arg = name + "="; 
         var alen = arg.length; 
         var clen = document.cookie.length; 
         var i = 0; 
         while (i < clen) { 
             var j = i + alen; 
             if (document.cookie.substring(i, j) == arg) return getCookieVal (j); 
             i = document.cookie.indexOf(" ", i) + 1; 
             if (i == 0) break; 
         } 
         return null; 
} 

//将浏览动作写入cookie
function setCookie (name, value) { 
       value = escape(value);
	   var Days = 30;
       var exp = new Date(); 
       exp.setTime (exp.getTime()+ Days*24*60*60*1000); 
       document.cookie = name + "=" + value + "; Path=/; expires=" + exp.toGMTString()+ "; domain=" + domain;
}