Getting error with at.js

Hi Team,

I am now moving from mbox.js to at.js. The functionality was working fine with mbox.js and not in at.js. Below is the changes I had. Please let me know what could be the issue

1. I had added below script before a button for which a link was to be changed for Experience B

<div class="mboxDefault"></div><script type="text/javascript">

    mboxCreate('target-global-mbox','profile.test=test');

</script>

2. I added an Audience based on the value profile.test = test value

3. For this Audience I am editing the link of a button for Experience B using the Enhanced composer.

So the above worked fine for mbox.js implementation. I am getting the error "uncaught TypeError: c(...).addClass is not a function".