WebAIM - Web Accessibility In Mind

E-mail List Archives

Re: EM vs. REM?

for

From: Jukka K. Korpela
Date: May 30, 2013 10:37AM

2013-05-30 19:18, <EMAIL REMOVED> wrote:

> I haven't seen anyone on any of the accessibility forms talk
> about REMs.

There isn't much to talk about it, since it adds no expressive power to
CSS and offers no accessibility benefits.

> As far as I can tell from various websites I see
> around, it seems to be getting primarily used by people who
> resisted switching from pixel dimensions to relative at all, as a
> more comfortable way of switching.

That's possible. Using rem is like using em, just simpler from a naive
perspective and with essentially limited browser support. Authors who
work with pages containing font-size settings on nested elements may get
confused - say, if you have body { font-size: 16px } (yes, those people
often set the basic font size in pixels, defeating the very idea of em
rather effectively) and a div inside with font-size: 90% and then inside
that div another div with font-size: 80%, and then they want to set
something in terms of "body em". They would need to do some calculations...

I don't see any point in using rem if you wish to cover all major
browsers, since you would still need to use em valued settings as backup
- so why not simply use em?

Yucca