SanfordWhiteman

@Brennan M, @Melissa M isn't using Marketo forms at all (neither directly on an LP nor using the embed code). The forms are bespoke forms that presumably result in a subsequent server-side form post that we can't see.So the field names and values that are passed to Marketo can't be directly controll...

You can still pass values into hidden fields via cookies or query parameters with an embedded form. However, prefill (where an associated lead cookie automatically pulls data in from Marketo) won't work with the embedded option.

OK, I threw together a landing page and reduced your code to the apparent problem area, but I don't see a problem. http://pages.vaneck.com/jq-whenready.html listens for the MktoForms2.whenReady event and then adds an Element.onChange event listener to the `Email` field, using jQ syntax for the nativ...

How about a URL where that code is running, so I don't have to make my own landing page?

@Craig N if a page has two form containers with the form ID, i.e.

The goal isn't entirely clear (sorry!) without example code/URL.Try to create an example of code that triggers the failure (rather than code you fixed with a workaround) and post the URL.

First thing I'd do is add this JS snippet:for ( var mktoRows = document.getElementById('mktoForm_1217').querySelectorAll('.mktoFormRow'), i = 0, imax = mktoRows.length; i < imax; i++ ) { mktoRows[i].setAttribute('data-wrapper-for',mktoRows[i].querySelector('.mktoField').getAttribute('name'));}What ...

You can still use the LP -- just turn off Prefill. I should've said Prefill takes effect if you leave it on.

Remember that prefill takes effect on LPS. So if a field's value is literally an empty string, that's going to appear instead of the form's default.Can you post the URL of the LP? Also, are you testing using an incognito/private browsing window?