Vital to note is that you can use multiple attribute selectors in the same selector, which requires all of them to match for the selector itself to match.
This is where it starts getting more interesting. The equals sign in attribute selectors may be prefaced by other characters which alter the meaning a bit. For example, "*=" means "match the following value anywhere in the attribute value."
Wordoff applies the following rules to strip the cruft that is pasted into WYSIWYG editors from Word:
Attributes are removed for all elements except ss and s are removedEmpty elements are removedConsecutive line breaks are reduced to two