Popups: What are they good for?
This is the second article in a series on web usability and accessibility. In the first article I talked about one of my top web annoyances: opening links in new browser windows. Popups are very similar in nature but can sometimes serve a useful purpose.
By my definition a popup is a small window which is used to supplement the content of the main browser window. Therefore it's always displayed at a considerable smaller size than the parent window. In most cases popups only have a title bar and no location bar or navigation buttons.
What I don't consider to be popups are windows which contain a full website and are only opened to have it displayed at a certain width and height, without any buttons, without a location bar because it's hosted on a different domain, etc. As far as I'm concerned those are all different versions of a 'new browser window'. If you read my first article you know the reasons why this is a bad idea.
The rise and fall of popups
It didn't take very long for online advertising companies to use popups as
a new means to get the users attention. Up until then banner ads where the
main form of online advertising.
Since then popups have been abused so much and users got so annoyed by them that all modern web browsers support some form of popup blocking.
Popup blockers try to prevent any new windows from opening automatically and only allow popups when a user performs some action (clicking a link for instance). This doesn't mean advertising companies have stopped using them or didn't try to circumvent them but it has made them a lot less effective as a marketing tool. Coupled to that the very succesful and effective text based ads (like Google AdSense) leads me to believe popup adverts will become less and less frequent in online advertising.
Is there any use for popups?
Although it wouldn't seem that way I can think of two possible uses for popups:
Modal dialogues are used when users need to provide certain information or make choices before they can continue. An example of this would be the 'close without saving' dialogue in Microsoft Word. When a user tries to close a document without saving the application asks a user what to do next. Either discard the changes or save the document. It's not possible to do anything else unless a choice is made.
Modal dialogues aren't used very often because most browsers don't support this type of behaviour (Internet Explorer is the only exception I know of which does). It's hard to block a user from using the existing window while a popup is shown.
Contextual help can be useful in transactional websites like web shops. A web shop checkout normally consists of a series of pages containing forms. These can sometimes be difficult to understand so its helpfull when a user is able to find out more about a certain feature. Allowing a user to open a small help window allows them to continue uninterrupted by simply closing the popup.
Problems using popups
There are certain limitations which you should be aware of when trying to implement popups into your website.
"Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page."
Not letting users know what's going to happen
If your somewhere in the middle of a web shop checkout what will happen when you click a help link? Will it open in a new window, in a popup or replace my current page? It's crucial to inform the user of what's going to happen so they don't have to worry about loosing anything they have done up until that point. Checkpoint 10.1 from the Web Content Accessibility Guidelines describes:
"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."
Popup blockers can block your popups
This seems pretty obvious but there's no guarantee that a popup blocker
won't block the popup. If you want to be a 100% sure this doesn't happen
you shouldn't use popups.
Also don't ask users to enable popups for your website because there's absolutely no guarantee they will or are even able to.
Users don't like popups
And that's putting it mildly. Because popups have mainly been used for advertising most people have a tendency to close popups as soon as they appear.
Popups must be distinguishable from the main browser window
As I wrote at the beginning of this article popups should supplement the content of the main browser window. Else your just opening new browser windows and those have a lot of usability problems as well.
Popups have a useful but limited purpose. When used correctly there's no reason not to use them however it's a lot of work to make an accessible website which relies on popups. In those situations I would try to avoid using them alltogether.