Link of the day ! "DOM Deviations", sorry "Normative Variations"

The following subsections detail the normative variations from MUST requirements in [DOM Level 3 - Core].

http://msdn.microsoft.com/en-us/library/ff460357(v=VS.85).aspx

Or even better:
Internet Explorer Standards Support Documents

http://msdn.microsoft.com/en-us/library/ff405926(v=VS.85).aspx