A farewell to pop-ups

TripAdvisor's pop-up all but blocks everything else on screem
TripAdvisor’s pop-up all but blocks everything else on screen

Comment added in 2022: These days we use the term ‘modal’ instead of ‘pop-up’ and I don’t see as much discussion of pop-up blockers. Otherwise, I think this is still accurate. CJ.  

Do you remember the olden days on the web, when we’d watch participants struggle because they didn’t know about scrolling? And they’d only click on a link if it were blue and underlined?

At that time, the rule for pop-ups was simple: “Pop-ups: just say NO”.

Gradually I started to notice that pop-ups weren’t confusing my participants. Providing the pop-up conformed to certain rules, it was just fine. After some email discussion with Carl Zetie of Forrester Research, we formulated the ‘Jarrett-Zetie Rules of Pop-ups’. If a pop-up satisfied all of the five rules, then it was likely to be usable.

The Jarrett-Zetie rules of pop-ups

1. Expectation

The user expects new content, and expects that content to be a diversion from the current task rather than intrinsic to it.

2. Context

There is some advantage to the user in seeing the new content on screen at the same time as the existing content.

3. Size

The pop up size is between one quarter and one third of existing window size. (If the size is less than one quarter, then the content should be moved onto the main page. If the size is more than one third, then you break the rule of context).

4. Knowledge

The user isn’t thrown by pop-ups and knows how to close them.

5. Single use

There is only one pop-up at a time, and you have some way of being sure that the pop-up comes to the front.

Recently, I have been finding more and more evidence that too many pop-ups break the rules. Here are three examples.

Pop-up blockers

Advertisers ruin the customer experience on some websites by hurling obtrusive pop-ups at you. Some of the cannier ones realise that these break the rules of Expectation and Context, so they use ‘pop-unders’ instead – the pop-up that hides behind the current window, to appear when you end the current window. These just break the rule of Expectation. Result? Many people these days run a pop-up blocker, a little background program that stops pop-ups and pop-unders. Although the blockers try to discriminate between intrusive advertising pop-ups and a pop-up that you have requested, I’m not convinced that they succeed.


The Disability Rights Commission (DRC) recently published the report on its Formal Investigation into Web Accessibility. The report lists eight of the Web Accessibility Initiative’s checkpoints as being especially important for disabled people in this sample, as violations of these checkpoints caused the majority of problems encountered. And there it is: checkpoint 10.1. “Until user agents allow users to turn off spawned windows, do not cause pop-ups or other windows to appear and do not change the current window without informing the user”. It seems that disabled people are especially prone to violations of the rule of Knowledge.

Let’s think it through. I’ve fought my way past a selection of links and focused my attention on a small chunk of a complicated page. I click… and bingo, I’m expected to switch focus from the point where I clicked to some random point in another window. A few examples:

  • If I’m using a screen magnifier then that new point may be off the screen.
  • If I’m dyslexic or have an attention disorder then I’ve got to start all over again and orient myself to a new window.
  • If I’m using a screen reader then it may not notice that the pop-up has appeared.

Not good, is it?

Well-intentioned misuse of modes

Last, and probably least, there is a pet peeve of my own. About one time in ten when I use Adobe Acrobat 5.0 (the full version, not the reader) it inexplicably locks up. After a while, I realised that this isn’t a defect: it’s a ‘helpful’ feature. The dear little program is trying to help me by nipping out onto the web to check for a newer version of itself, and it does it by popping up a dialogue box asking if I want it to do so. But the dialogue box is modal, so the program locks up while the dialogue sits unanswered. Why is that a problem? Because too frequently the ‘!*%#’ dialogue box pops under instead of popping up, thus appearing to lock up Acrobat. This is a violation of the rule of Single Use. I’m sure that this isn’t the only example but it is the one that annoys me most frequently.


I’m going back to my old stance. The rules are broken too often for them to be useful. From now on, it’s going to be “Pop-ups: just say NO”. Unless the designer can convince me that they will obey all five rules meticulously.

This post first appeared in Caroline’s Corner, Usability News