The outcome of comparing one attribute: 0 when it is the same, 1 when it is missing or different, or - for the multi-part attributes (style, class) - the list of what each part of it looks like (see compareArrays).
The outcome of comparing one attribute: 0 when it is the same, 1 when it is missing or different, or - for the multi-part attributes (style, class) - the list of what each part of it looks like (see compareArrays).