My CSS 3 Browser Compatibility List

Table of contents:

Which web browser uses which rendering engine?

Rendering engine	Release date	Web browser	Is it safe to rely on this version?	Documentation
Presto 2.0	2006-06	Opera 9.0	superseded (1%)
Presto 2.1.x	2008-06	Opera 9.5 and 9.6	superseded (4%)	Web specifications supported in Presto 2.1.x
Presto 2.2.x	2009-09	Opera 10.00 and 10.10	yes (90%)	Web specifications supported in Presto 2.2
Presto 2.3		Not used in the desktop browser		Web specifications supported in Presto 2.3
Presto 2.4		Not used in the desktop browser		Web specifications supported in Presto 2.4
Presto 2.5.x	2010-03	Opera 10.50	not yet (4%)

Rendering engine	Release date	Web browser	Is it safe to rely on this version?
Gecko 1.7	2004-11	Firefox 1.0	superseded (<1%)
Gecko 1.8.0	2005-11	Firefox 1.5	superseded (<1%)
Gecko 1.8.1	2006-10	Firefox 2.0	superseded (2%)
Gecko 1.9.0	2008-06	Firefox 3.0	superseded (4%)
Gecko 1.9.1	2009-06	Firefox 3.5	yes (45%)
Gecko 1.9.2	2010-01	Firefox 3.6	almost (48%)

Rendering engine	Release date	Web browser	Is it safe to rely on this version?
WebKit 522.x	2007-06	Safari 3.0.x	superseded (<1%)
WebKit 525.x	2008-03	Safari 3.1.x and 3.2.x	superseded (2%)
WebKit 528.x	2008-12	Google Chrome 1.0	superseded (3%)
WebKit 530.x	2009-06	Safari 4.0 to 4.0.2, Google Chrome 2.0	superseded (<1%)
WebKit 531.x	2009-08	Safari 4.0.3 to 4.0.4	yes (55%)
WebKit 532.x	2009-10	Google Chrome 3.0 and 4.x	not yet (39%)
WebKit 533.x	2010-02	Google Chrome 5.0	no (1%)

Rendering engine	Release date	Web browser	Is it safe to rely on this version?
Trident (unversioned)	2001-08	Internet Explorer 6.0	yes (21% of the IE users)
Trident (unversioned)	2006-10	Internet Explorer 7.0	superseded by 8.0
Trident 4.0	2009-03	Internet Explorer 8.0	yes if you don't care about the 21% IE6

CSS property	Opera (Presto)	Firefox (Gecko)	Safari (WebKit)	Internet Explorer
`rgb(100%, 100%, 100%)`	since 3.5	all	all	since 4.0
`hsl(360, 100%, 100%, 0.5)`	since 9.5	all	since 3.1	none
`rgba(100%, 100%, 100%, 0.5)`	since 10.0	since 3.0	since 3.1	none
`hsla(360, 100%, 100%, 0.5)`	since 10.0	since 3.0	since 3.1	none

My conclusions:

It does not matter if you use #FFFFFF or #FFF or rgb(255, 255, 255) or rgb(100%, 100%, 100%). It's all well supported for many years now.
I will not use hsl yet. It may improve the readability of my CSS source code but brings no benefit to the design. I will use a calculator to convert hsl values to rgb.
I will start to use rgba in cases where it's no problem if you see a solid color instead. I will always add a fallback as described here.

Documentation:

CSS property	Opera (Presto)	Firefox (Gecko)	Safari (WebKit)	Internet Explorer
`text-shadow`	since 9.5	since 3.5	since 1.1, multiple shadows since 4.0	none (supports filters since 5.5)
`box-shadow`	since 10.50 (2.3)	since 3.5 (as `-moz-box-shadow`)	since 3.0 (as `-webkit-box-shadow`)	none (supports filters since 5.5)

My conclusions:

Starting in 2009 text-shadow is supported by all browsers except Internet Explorer. I use it. However, it's very importand the text is still readable without the shadow. Never ever rely on a shadow, not now and not in the future.
I don't use the Microsoft filters in Internet Explorer because they look ugly in most cases.
Support for box-shadow is still experimental in all browsers. Use it only in cases where it's no problem if the shadow is missing.

Documentation:

CSS property	Opera (Presto)	Firefox (Gecko)	Safari (WebKit)	Internet Explorer
`word-wrap: break-word`	since 10.50 (2.3)	since 3.5	all	since 5.5
`text-overflow: ellipsis`	since 9.0 (as `-o-text-overflow`)	none	since 1.3	since 6.0

My conclusions:

I think it's a good idea to use word-wrap: break-word in all cases where long words are displayed in narrow columns. However, I do not rely on it. The support was added very late in Firefox (2009) and Opera (2010).
I try to avoid text-overflow because it shortens words (e.g. “abbreviations” becomes “abbrev…”).

Documentation: