Getcookie(name) 获取cookies方法 ，name为名字
Setcookie(name,value,interval,number,[path],[domain],[secure]) 设置cookies方法
  name 名称，value cookies值，interval（"y" 年,"q"季,"m"月,"d"日,"h"时,"M"分,"s"秒，默认：日），number：数量级
  [path],[domain],[secure] 可缺省。
Delcookie(name)  删除设置过期cookies ， name：cookies名称  
mr.junval@qq.com 2008
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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;
    }
    
    function Delcookie(name){
        var exp = new Date();
        exp.setTime (exp.getTime() - 1);
        var cval = Getcookie (name);
        document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString();
    }
    
    function Setcookie(name, value,interval,number){
        if (interval == "0") return false;
        var expdate = new Date();
        var argv = Setcookie.arguments;
        var argc = Setcookie.arguments.length;
        var expires = DateAdd(interval,number,expdate);
        var path = (argc > 4) ? argv : null;
        var domain = (argc > 5) ? argv : null;
        var secure = (argc > 6) ? argv : false;
        document.cookie = name + "=" + escape (value) +((expires == null) ? "" : ("; expires="+ expires.toGMTString()))
        +((path == null) ? "" : ("; path=" + path)) +((domain == null) ? "" : ("; domain=" + domain))
        +((secure == true) ? "; secure" : "");
    }
    
    function DateAdd(interval,number,date){
        switch(interval){
            case "y":{
                date.setFullYear(date.getFullYear()+number);    
                return date;    
                break;  
            }
            case "q":{
                date.setMonth(date.getMonth()+number*3);  
                return date;    
                break;  
            }
            case "m":{
                date.setMonth(date.getMonth()+number);    
                return date;    
                break;  
            }
            case "w":{
                date.setDate(date.getDate()+number*7);  
                return date;    
                break;  
            }
            case "d":{
                date.setDate(date.getDate()+number);  
                return date;    
                break;  
            }
            case "h":{
                date.setHours(date.getHours()+number);    
                return date;    
                break;  
            }
            case "M":{
                date.setMinutes(date.getMinutes()+number);    
                return date;    
                break;  
            }
            case "s":{
                date.setSeconds(date.getSeconds()+number);  
                return date;    
                break;  
            }
            case "0":{  
                return date;    
                break;  
            }
        }            
    }