For the most part these browsers partially support the numerical scale, but only for two weights; Regular and either Bold or Semibold.

A workaround

There is a workaround. Following on the heels of Guillermo Esteves, it involves the clever addition of some font-families. As well as the font’s family name – Myriad Pro in the test case – each installed font weight has two other names: the screen name, eg. Myriad Pro Light and the PostScript name, eg. MyriadPro-Light (to find these names, use a font management tool such as FontExplorer X and click info for the font). To get Opera, IE 8, Firefox 2 and Firefox 3/Win to render an alternative weight, you need to specify the screen name, so the test case would need to be modified as follows:

#one { font-weight:100; font-family:"Myriad Pro Light", "Myriad Pro"; }

However this doesn’t work in Safari, which needs the PostScript name. So your styles need to be further modified, as in the modified test case:

#one { font-weight:100; font-family:"MyriadPro-Light", "Myriad Pro Light", "Myriad Pro"; }

There are distinct downsides to this workaround. Obviously the first is that you need to specify at least three font families just to change the weight. But the main problem is that font-weight will no longer work (apart from in Firefox 3/Mac) as the font-family you are now specifying only contains the one weight. So if you need an Bold word within a Light weight paragraph, you’ll have to specify the font-family as well as the font-weight . Not very practical.