My site comes across many instances where I'd like to use a modal. Sign up, sign in, comments, and file uploading are a few examples.

Now, I can go with a conventional modal design where the modal is typically fairly small in size and you're able to see the page in the background (behind a transparent black overlay), like the one below:


Or I can go with a fullscreen modal design, like the one below. I find that fullscreen modals look better and cleaner.


What are the disadvantages of using a fullscreen modal? Should I go with the conventional modal design or the fullscreen modal design?

1 Answer 1


I just went through this same process last week, first starting with full screen modal and then retracting it back to a "standard" modal.

TL;DR users will hit the back button in the browser.

This experience was for web UI (bootstrap) - from your screenshot it looks like you are using bootstrap or something similar. You have tagged this as "webapp" so I think I'm on track.

My desire to use a full screen modal (which required a variety of CSS mods in bootstrap) was to not distract the user with the content "behind" the modal. The result looked good, and worked fine as far as I was concerned. The moment I let a coworker interact with the full screen modal i knew I was in trouble. If he opened the modal mistakenly, he would immediately hit the "back" button in the browser. This of course would take him to a completely different view from where he started from, losing any other progress he made in the initial view.

  • 1
    I've thought of this. Couldn't this easily be solved by appending #modalName to the end of the URL? If the user hits the back button, it should remove the modal. gist.github.com/thedamon/9276193
    – user91668
    Commented Sep 27, 2016 at 6:19
  • In some cases sure - but browser page navigation will very likely wipe out any JavaScript / form state you may be trying to retain in the parent view. Commented Sep 27, 2016 at 6:24
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    Sometimes, you might want to have the background page "shine through" as a teaser to sign up. So, it doesn't necessarily distract it might even attract users
    – tofro
    Commented Oct 26, 2016 at 19:49
  • this behavior you've observed from your users is actually a sign that non-modal is the preferred solution. If your users want to navigate using back button, it's because that is a behavior they expect to be able to use on the web. don't take it away from them by using a modal.
    – kenwarner
    Commented Apr 10, 2017 at 18:50
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    @MichaelHeraghty I think the key to correctly implementing a full screen modal is to ensure “back” commands get correctly translated to closing the “modal”. At the time I wasn’t aware of the JavaScript pushstate API. Commented Jan 17, 2018 at 14:46

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