js 操作cookie

function setCookie(c_name, value, expiredays) {
        var exdate = new Date()
        exdate.setDate(exdate.getDate() + expiredays)
        document.cookie = c_name + "=" + escape(value) + ((expiredays == null) ? "" : ";expires=" + exdate.toGMTString())
    }

function getCookie(c_name) {
        if (document.cookie.length > 0) {
            c_start = document.cookie.indexOf(c_name + "=")
            if (c_start != -1) {
                c_start = c_start + c_name.length + 1
                c_end = document.cookie.indexOf(";", c_start)
                if (c_end == -1) c_end = document.cookie.length
                return unescape(document.cookie.substring(c_start, c_end))
            }
        }
        return ""
    }

function deleteCookie(c_name) {
        var date = new Date();
        date.setTime(date.getTime() - 10000);
        document.cookie = c_name + "=; expire=" + date.toGMTString();
    }