My idea originates from this Collector for ArcGIS tutorial demonstrating how to use relationship classes to establish a link between Hydrants and Inspections within Collector. The upshot of the tutorial is that, once a Hydrant is created, many inspections can be associated with that hydrant in an Inspections table.
Basically I want to replicate this behavior, but instead of using Hydrants and Inspections I want to establish this link between a Project Description layer and a Milestones layer. For instance, say I make a new Project in San Jose, CA using a Geo Form. I want to create the functionality that would essentially let users click a button that says 'Add a Milestone' and then they can update the Milestone related table with new information.
I have created a relationship class between my Project Description and Milestone layers in ArcGIS for Desktop and pushed it up to ArcGIS Online and have confirmed with test data that the the relationship exists. However, in order to Add records to the Milestone table, I've only been able to use either Collector for ArcGIS or ArcGIS for Desktop. Neither of these solutions are acceptable for my workflow, as I am developing an application for a client whose users will not be using either platform. The users can only interact with the data via a Web Mapping Application. Does anyone know of any method, custom custom widget or otherwise, to add data to a related table within ArcGIS Online without using Collector?