I have an email subscription form. I'd like to make it so that if any of the data on this form is left blank, it doesn't overwrite the current data in those fields on the lead record, as this is an initial subscribe form rather than an unsubscribe or subscription management page.
For instance, if a lead were already subscribed to 2 of our 4 lists, and use our subscription form to subscribe to a third, if they don't also check the checkboxes for the lists that they are already subscribed to they would be removed from them. From a user stand-point this seems counter-intuitive, if they were already subscribed, why would they need to subscribe again?
I contacted Marketo support and they said "In regards to not submitting data in a field if it is blank, this will be something that needs to be done by adding some Javascript code. On a high level, the Javascript will need to block updates from a field if it is left blank but was populated before."
Has any one tried this before? Do you have any work arounds or sample code that we could use as a starting off point (our web developers are kinda snowed under at the moment)?
This seems like something that should be a native option in Marketo...subscription pages are pretty standard in the industry.