They may appear in any order.
Attribute names are always case-insensitive.
Attribute values are generally case-insensitive. The standard HTML color specification methods. Values to this attribute are separated by commas, and represent the horizontal widths of the resultant separate child frames in the current parent frameset. In theory, all values listed should account for, or sum up to, the full parent frame size. It is possible to abuse this, because the three types of values can be freely intermixed.