如何修改Mailchimp Subscriber Pop-up（嵌入）cookie

Question

默认的到期时间是1年。我想要1周。

嵌入代码就是这个。

http://s3.amazonaws.com/downloads.mailchimp.com/js/signup-forms/popup/embed.js

如何做到这一点

    if(document.cookie.indexOf("MCEvilPopupClosed") > 0 ){

    //check if (Cookie was created more than 7 days){delete cookie} 

    }