I’ve been working with an organization that is still on SharePoint 2013 Foundation. Foundation does not support InfoPath so developers before my arrival were very creative. They used custom HTML forms and JavaScript utilities.
One thing users always ask for is Cascading Columns. Without form tools the only solution is JavaScript. Mark Rakley has posted an excellent solution called “Hillbilly Forms”. The only problem here is that it is not easy to support or extend. I like to “pramerterize” my solutions so that I can hand over the application to users and they can maintain it themselves.
I’ve been doing a lot of work with Content Types recently and it dawned on me that by using Content Types I could create a solution that provided a single cascading column. A bit of a workaround but play along.
Start by creating all the Columns that you will need as site columns in Site Settings, Site Coulumns. This will include all the columns that you want on your form as well as the Columns that you will be using as the Cascading Column.
In Site Settings Site Columns create a base Content Type that will be the parent Content Type that your unique Content Types will inherit from. Then create the Content Types that will act as your Cascading Columns. Inherit the Base Content Type as the parent Content Type.
After you have created all of your child Content Types you will need to add them to your list. In List Setting Choose Advanced, Allow Content Management. In the List Setting Content Types add your child Content Types. Remove the “Item” Content Type. You can also set your default Content Type.