We at Bazaarvoice have also been struggling with this. Marketo - please help!
It's the last code sample on this page: https://community.marketo.com/MarketoArticle?id=kA050000000Kyy3
Replace the yellow text with your exact field name
// set no conflict mode for jquery
var $jQ = jQuery.noConflict();
Thanks, Jep. That's the code I've been using. The problem is with leads who already have data in this field. For them, the old values for this field are still showing up in the drop down as an option. The value is saved in the lead record, but has been deleted as an option on the form. See below.
Here is the page URL where we're having the problem: http://resources.bazaarvoice.com/Connections.webinar.choice.html.
Any resolution to this? We also have this drop down field issue.