I'm not sure how best to approach this, but this project would require a popup to appear. The popup would display an iframe that has a donation form linked to an external database. Ideally, this popup would only appear if the visitor has not yet donated.
Since I don't have direct access to this external database (form is provided by the client), I thought, maybe, the popup could utilize HTML localStorage (found a working demo here) taking it a step further to check if that form had been submitted (storing info from the form action?) for that visitor. This stored cookie would then expire every 6 months.
Is this even possible or is there a better way to accomplish this?