dd.ready不执行

var _config = <%= dingding.Dding.getConfig(request) %>;
alert(_config.signature);


dd.config({
            agentId : _config.agentid,
            corpId : _config.corpId,
            timeStamp : _config.timeStamp,
            nonceStr : _config.nonceStr,
            signature : _config.signature,
            jsApiList : [ "runtime.info', 'biz.contact.choose",
                    "device.notification.confirm", "device.notification.alert",
                    "device.notification.prompt", "biz.ding.post",
                    "biz.util.openLink" ]
        });




dd.ready(function() {
    dd.biz.navigation.setTitle({
        title: "钉钉demo",
        onSuccess: function(data) {
        alert(data);
        },
        onFail: function(err) {
            log.e(JSON.stringify(err));
        }
    });


我的dd.ready不执行，
agentId : _config.agentid,
corpId : _config.corpId,
timeStamp : _config.timeStamp,
nonceStr : _config.nonceStr,
signature : _config.signature,
这五个都有值，可以打印出来。为什么啊，请大神帮忙看看！谢谢