WebKit Bugzilla
document.execCommand("FontSize", false, str); Before passing "10px" to this function produced: <SPAN class="Apple-style-span" style="font-size: 10px;">Text</SPAN> Now this gives me no matter what I pass: <span class="Apple-style-span" style="font-size: -webkit-xxx-large;">Text</span> compactible format, with much less control unless there is another web kit command to pass a font size with a point or pixel value.
We changed this operation to match the spec: http://msdn.microsoft.com/workshop/author/dhtml/reference/constants/fontsize.asp
I just did a little testing with the lastest nightly. You can set the font-size using .execCommand('FontSize' and values 1-7, but .queryCommandValue('FontSize') returns the font-size in pixels... Not consistent units! Is there a way to convert the result of .queryCommandValue('FontSize') to the corresponding 1-7 value in order to increment font size?
I think this bug should be reopened. Comment #1 indicates that the behavior was changed to match Microsoft's spec. The provided link is dead, but I believe the following link replaces it: http://msdn.microsoft.com/en-us/library/ms530759(VS.85).aspx Based on the information in that spec, I should be able to specify 14pt or 14px (among a number of other types). However, WebKit just converts these to -webkit-xxx-large.