Pop-up to confirm action in Shiny

It’s a gorgeous evening in Bath tonight, and my evening has been improved by finding a free table outside at the pub, a large glass of Sauvignon Blanc, and working out how to include a JavaScript confirmation box in Shiny. Here, I’m using Shiny dashboard, although this methodology will work fine with other UI layouts.

In the UI file, near the top of the dashboardBody, call tags$head and tags$script to give the source of the JavaScript file:

tags$head(
  tags$script(src = 'custom.js')
),

Then, in a file named custom.js as above, within the www folder, include the following code. Here, the button which the user clicks on has the inputId set to “submit”.

$(document).on('shiny:inputchanged', function(event) {

  if (event.name === 'submit') {

    var r = confirm("Are you sure you want to continue?");

    if (r === false) {
      event.preventDefault();
    }

  }

});

Want to know more about JavaScript events in Shiny? Visit this article on the RStudio website for a comprehensive guide: http://shiny.rstudio.com/articles/js-events.html