Last three columns show equivalent SIZE number on Windows 98 SE. (ie SIZE="" results in a field as wide as a SIZE=20 in IE and as wide as a SIZE=1 field in NS. It does not reflect how many characters that actually fits.)
Notice how Mozilla (2000-07-20) treats "NaN" differently from other invalid values like "XYZ" for example.
I think Mozilla does the right thing in the first 6 cases,
bug the rest should be treated as SIZE=20 (as IE5 does.)