cookie操作

　　//记录cookie值
        function setCookie (name,value){
            var Days = 30;
            var exp = new Date();
            exp.setTime(exp.getTime() + Days*24*60*60*1000);
            document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
        };
    //获取cookie值
        function getCookie (name){
            var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
            if(arr !== null){
                return unescape(arr[2]);
            }else{
                return null;
            }
        };
    //删除cookie值
        function deleteCookie (name) {
            var exp = new Date(); 
                exp.setTime(exp.getTime() - 1); 
                document.cookie = name + "=; expires=" + exp.toGMTString();
        };