An emergency workaround for app-𝑛𝑛𝑛𝑛 form embeds after next week’s Marketo URL change

Level 10 - Community Moderator
Level 10 - Community Moderator

Been reluctant to provide a short-term workaround for the rather big change coming next week to Marketo URLs. But based on recent research, I have the sense that many people’s form embeds will be impacted on August 1st, so let’s prevent a bad day in MOPSville.


You want to put these two scripts as high as possible in the <head> of all pages, of course replacing in both places with your LP domain:

<script src="//"></script>
   "use strict";

   MktoForms2.loadForm = new Proxy(MktoForms2.loadForm, {
      apply(target, thisArg, [instanceURL,]) {
         return Reflect.apply(target, thisArg, ["//",]);


By β€œas high as possible” I mean literally right after your last <meta> tag if you can. It must run before anything else related to Marketo forms, including GTM (which might inject Marketo form tags).


If you have this in place, you don’t have to worry about finding all the occurrences of the Forms 2.0 library and loadForm() calls throughout your code.


The right thing to do long-term is, of course, find and permanently fix all form embed codes  that use the old domains. But the β€œfinding” part can be tricky, as can getting the right person to implement the fix.


P.S. I’ll update this post with more info about why the above works, for the JS learners.