We're going to use the Gapminder application we've been looking at throughout the book, but add a little JavaScript magic. We're going to add a button that, when clicked, writes the currently selected years on the summary text tab. Let's take a look at what we're adding to the ui.R file, over in the sidebarPanel() function:
tags$input(type = "button", id = "append", value = "Add current input values", onClick = "buttonClick()"), includeHTML("appendText.js")
As you can see, we use the tags$xxx() function that we saw in Chapter 3, Integrating Shiny with HTML, in order to generate a button that will run a JavaScript action when it's clicked. It generates the following HTML:
<input type="button" id="append" value="Add current input values" ...
