Modals are a UI element from Bootstrap and are pop-up messages that can tell your user more about what the application is doing. They can be useful to give a user warnings, or to allow the user to request more information about an output if they wish to know more. You can write a modal very simply, using two functions in the server.R file. The modalDialog function produces the modal, and the showModal function shows it. You can use them together just like this:
showModal(modalDialog(
title = "Warning",
"This is a warning"
))
This will give us a simple dialog with a title and a main section:
But we can do more interesting things than this with modal dialogs. There are two ways that we can expand their functionality. First, because the modalDialog() function will accept any Shiny UI elements, not just text, you can add HTML elements such as horizontal...
