Checkpoint 3.4 question
| Quote: |
| 3.4 Use relative rather than absolute units in markup language attribute values and style sheet property values. |
This checkpoint is one of much debate in my office and I would appreciate feedback from others on this one. If I create a design which is resolution independent but say the left nav has a fixed width of 150px, is this a failure of this checkpoint? There's nothing in the WAI guidelines which gives us specific details of which attributes should be relative. I mean surely specifying a border of 1px is hardly a failure of 3.4??
Opinions please
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A 1px border is probably not a problem in real life. A 150px left nav may cause severe problems in a low-resolution (PDA, cell phone, etc) or high-resolution (laser printer) output device. Also, if a user with low vision sets his base font size to 72px, will your left nav still be useful with perhaps only two or three letters per line?
It's generally better IMHO, if possible, to use ems for the width of a nav bar. I know many like to use px for this, because they use a tiled background image to emulate a full-height column, but it's difficult to make it accessible.
But what about stuff that has a physical real-world dimension that we'd like to preserve? Shouldn't we be allowed to use specifications such as 17.5cm or 4in for those?
I think we should use a lot of discression when we interpret this particular guideline. To me it says, "be careful with specifying the size of things in a way that may display badly in some hardware devices."
In your case, you'll probably need a different style sheet for printing (no problem) and, possibly, for handheld stuff (more of a problem, since some of these seem to read screen styles as well).
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Since the pixel is a relative unit then there is no failure, just some considerations.};-) http://www.xhtmlcoder.com/
WVYFC chose the Yorkshire Air Ambulance as the main charity to fund raise for in 2006
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Handhelds read screen styles? What media="screen"? Isn't that then a failure of the manufacturer to implement CSS properly, and therefore not our responsibility to cater for?
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| brothercake wrote: |
| Handhelds read screen styles? What media="screen"? Isn't that then a failure of the manufacturer to implement CSS properly, and therefore not our responsibility to cater for? |
in an ideal world ? yes, it's the manufacturer's responsibility.
in the real world though, one has to make compromises (hopefully only temporarily, mind).
Patrick H. Lauke / webmaster / University of Salford
co-lead: WaSP Accesibility Task Force
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Compromise yeah .. but only up to a point. If we go too far we perpetuate vicious circles.
Which PDAs is it that do this?
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I'm afraid I don't know which PDAs/cell phones read style sheets with media="screen", nor can I remember where I read it. I do remember reading it, though.
Apparently the browser manufacturers for these devices know that few web pages have a specific style sheet for media="handheld", so in order not to display unstyled content for 99.9% of all web sites, they decided to make a stab at media="screen" as well. Unfortunately, they didn't do a very good job of implementing CSS, so they read the screen style sheets and botch them up completely. The result is that any style sheet more advanced than pure vanilla will be a disaster.
We have the same problem with screen readers, don't we? We'd like to think of them as aural browsers, but they are not. They are often layers on top of a regular browser, which will read style sheets with media="screen", and completely ignore style sheets with media="aural".
Sooner or later these things will probably sort themselves out (unless spammers kill the Web first), but until then we're kind of stuck.
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I know for certain that the first browser bundled with Palm OS 5 read only "screen" CSS and ignored "handheld" entirely. Supposedly the latest version of their browser allows you to switch between the two, but I have yet to download it and try it.
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