I'm sure there is a simple answer, but I can't find it - or are searching improper terms.
Is there a way to allow a website visitor to "add" content to an existing drop down menu?
Have a drop down menu with a couple of pre-existing street addresses. If one isn't listed, I'd like for the end-user to be able to add their street address - which is then added to the list in the drop down menu?
This isn't currently a feature of Gravity Forms. If you wanted to do this you'd have to do it as a customization. You would have to make a Drop down option called "Other" that then displays a Single Input field using conditional logic where the user would input their address.
You could then write custom code to dynamically populate the drop down on the front end so it uses both the values you populated AND queries entry data to pull in any users have entered in the Single Input Field.
As this is a customization, you would have to write the code in order to do this.
Here is a tutorial on dynamically populating a drop down field:
http://www.gravityhelp.com/documentation/page/Dynamically_Populating_Drop_Down_Fields
