I don't understand why people write CSS this way...

[ka jowct]

I always use px. It ensures that the design & layout of the site remain intact. The purpose of the sites (at least that I typically work on) is to convey a message to the user. Losing control of how the typography flows can completely change the message. I will provide a method for users to adjust type sizes on the site - still using px - before I'll allow a browser to miscommunicate my message.

It ensures no such thing. AFAIK, setting type in px only keeps things "intact" for some people using some versions of Internet Exploder.

Are you using CSS for structure or just for text styles? There are ways to minimize browser differences.

If maintaining exact text flow is so critical, the web is not an ideal medium for your message, unless you want to convert the text to graphics, which is not a good solution.

To me it would make more sense to figure out ways to deliver your message that can take advantage of what the web does well.

[M A V I C]

[quote ka jowct]It ensures no such thing. AFAIK, setting type in px only keeps things "intact" for some people using some versions of Internet Exploder.
Oh but it does. Em's are far worse at it. Using px sizes does most certainly ensure an intact layout for IE users up until IE7. It changes things some, but I can still ensure a large percentage of customers receive the intended experience by using px.

Are you using CSS for structure or just for text styles? There are ways to minimize browser differences.

It depends on the situation. Always for text, often for layout.

If maintaining exact text flow is so critical, the web is not an ideal medium for your message, unless you want to convert the text to graphics, which is not a good solution.

I agree that graphics are not the way to go. All of my clients use print as well, but we don't sacrifice quality of messaging on the web when we don't have to. From protecting from basic things like widows and orphans, to ensuring captions align properly, rows align... using px sizes greatly contributes to the legibility, usability and communication of the site. The web is another form of communication, and it's always best to communicate as clearly, effectively and efficiently as possible.

To me it would make more sense to figure out ways to deliver your message that can take advantage of what the web does well.

I'm not sure what you mean by that. Using em's for type control is something that doesn't work very well for most of my intended purposes on the web. It's akin to pre-CSS days. And type control has always been a problem on the web, especially before CSS.

[ka jowct]

It changes things some, but I can still ensure a large percentage of customers receive the intended experience by using px.

It is possible to have a great deal of control using ems, and it allows people using IE to resize text fairly easily if they need to.

px sizes can be scaled up and down by people using browsers other than IE for Windows.

I'm guessing that if you are trying to control things like widows and orphans, you aren't using fluid layouts.

[M A V I C]

[quote ka jowct]It changes things some, but I can still ensure a large percentage of customers receive the intended experience by using px.

It is possible to have a great deal of control using ems, and it allows people using IE to resize text fairly easily if they need to.

px sizes can be scaled up and down by people using browsers other than IE for Windows.

I'm guessing that if you are trying to control things like widows and orphans, you aren't using fluid layouts.
With ems being relative, that automatically negates a ton of control. Yes, you still have a lot of control, but you lose a bunch too.

PX sizes can be scaled in other browsers, but typically if someone is using a different browser (like Firefox) they know a little more about web browsers than many users.

We've received more feedback from users stating that a given site is tough to read, on sites that allow the browser to resize the type than on sites where we've fixed the font. The reason being is they often get their font size changed and don't remember how to change it back.

The majority of sites that switched to fluid layouts from about 2000 to 2005 have stopped. The overwhelming vast majority of major sites all used fixed layouts. Fluid layouts, such as this forum, are extremely rare.