Originally Posted by burbleburble
I looked into friendly-name/number by font-weight; it appears that for many browsers there is no difference between 100-400, 500-600, etc. Could you provide me with a source that 400 must equal regular, etc?
The additional granularity of 100-900 is only useful if the renderer can do something with it. Most of the time it can't, yet.
If you're just working with typical normal/bold fonts the renderer will pick the best match. So if you specify 300, it will use normal (400), etc.