[BOM] 封装一下cookie

    function get_cookie(key) {
        var arr, reg = new RegExp("(^| )" + key + "=([^;]*)(;|$)");
        arr = document.cookie.match(reg)
        return arr ? arr[2] : null
    }

    function set_cookie(key, value, day, domain) {
        var exdatestr = ''
        domain = domain || location.hostname
        if (day) {
            var date = new Date()
            date.setDate(date.getDate() + day)
            exdatestr = ';expires=' + date.toGMTString()
        }
        var cookie = key + '=' + value + exdatestr + ';path=/;domain=' + domain
        document.cookie = cookie
        console.log('document.cookie', cookie);
    }

//--------------------------------------------------------------
// 调用
set_cookie('once', '123', 24)
get_cookie('once')