More and more commercial websites are featuring pop-ups these days. In many instances, I'm noticing more pop-ups being used for advertising, probably due to the harsh reality that is "banner blindness". In other cases, pop-ups are used to display supplemental content to the parent page. Unfortunately, many designers know little about how to make a proper pop-up window that will be accessible.

Among the many concerns of accessible design is found in "Guideline 6" of the W3C's Web Content Accessibility Guidelines: http://www.w3.org/TR/WCAG10/#gl-new-technologies - "Ensure that pages are accessible even when newer technologies are not supported or are turned off." Simply put, you should ensure that your content remains accessible to those who modify their accessibility settings to disable scripting or whose choice of adaptive technology does not recognize scripting. See also the relevant Section 508 criteria: http://www.access-board.gov/sec508/guide/1194.22.htm#(l)

Popups are among the items that most often violate this accessibility guideline

A common pop-up window link will probably begin like this: <a href="#" onClick="window.open...... or: <a href="javascript:; onclick="window.open(....... In both instances, the link becomes completely unusable to those with scripts turned off or with browsers that do not recognize JavaScript.

From here on out, lets assume our target audience fits one of the two situations just mentioned - either they have JavaScript disabled or their browser cannot recognize JavaScript.

In the first case, using "#" as the hypertext reference will result, at best, in their being taken to the top of the page. The "#" sign is interpreted as what's known as a "Fragment Identifier Separator" ( see geekspeak at - http://www.w3.org/Addressing/URL/4_2_Fragments.html ). What this means to us is that the "#" is supposed to point somewhere, such as a named object on the page. It is not a default "Do Nothing" character. The hash symbol prepends the name of the target. So that <a href="#contact">Contact me</a> will take you to a place on the page that is named "contact" - <a name="contact"></a>

Using just plain "#" as the hypertext reference is bad because "A void fragment-id with or without the hash sign means that the URL refers to the whole object." In most browsers, it will be interpreted as pointing back to the beginning of the page. At best, it will do nothing when clicked.

In the second case, using "javascript:;" as the hypertext reference simply does nothing. Remember, we're dealing with those who for one reason or the other can't use anything dependent upon JavaScript. So again, this link does nothing for someone whose browser does not recognize javascript.

It can be done better and work well for all

Fortunately, we can create an accessible alternative that functions perfectly for those with JavaScript enabled, yet degrades well for those who don't. We do this by using a real link to the actual destination in our hypertext reference:

<a href="file.html" onclick="window.open('file.html', 'window_name', 'toolbar=yes, location=yes, status=yes, menubar=yes, scrollbars=yes, resizable=yes, width=xxx, height=xxx'); return false"> Open Window </a>

The above is the "accessible" method to open a popup (opening new windows is bad anyway, so I guess this is the lesser of two evils). Using the real file as the hypertext reference, but set the link to "return false" will operate properly whether the person has JavaScript enabled or not. Those without JavaScript enabled still get to the content, and those who have JavaScript get the popup as intended.

Now, here's the treat: Many people offer a means to close the pop-up that has just opened. Again, they do this with either <a href="#"... or <a href="javascript:;... Like so: <a href="#" onClick="window.close()">Close</a> Well, like I said before, all this does is take them to the top of the page. Assuming the popup is linked on only one page we can take them back by placing the referring file in the hypertext reference: <a href="referrer.html" onClick="window.close()">Close</a>

The use of the word "Close" might be confusing, but there are two schools of thought here.

1. By not opening the new window on those w/o JavaScript, the back button still works and will use this

2. Using a title will help them predict what will happen. Like so: <a href="referrer.html" title="clicking this link will take you back to the referrer if you don't have JavaScript" onClick="window.close()">Close</a>

Alternatively, you might also use the alt text attribute of a transparent spacer image: <a href="referrer.html"><img src="path/spacer.gif" width="1" height="1" border="0" alt="[Go Back]"></a> (This assumes they're also surfing with images off or on a non-graphical browser)

Ultimately, this comes down to what you hear me say so often: You cannot reliably predict the user or their settings. So don't try. Make it right and it will be usable to all.

Disclaimer:

Opening new windows is bad enough as it is. The above article only aims at showing you how to make them better. The best answer is to not use them at all. Please see the following links for details -

• Jakob Nielsen's Alertbox: The Top Ten New Mistakes of Web Design
  

• Jakob Nielsen's Alertbox: Top Ten Web-Design Mistakes of 2002
  

• Dive Into Accessibility: Day 16, Not Opening New Windows
  

• Dan's Web Tips: Opening New Browser Windows
  

Karl Groves is a freelance web designer who has done production work for such sites as National Cancer Institute, Network For Good and Aerospace Medical Association.