6.1 How the Almost Standards Mode is Implemented
Almost standards mode is triggered only when the DOCTYPE prolog specifies:
One of the following public identifiers:
"-//W3C//DTD XHTML 1.0 Transitional//EN"
"-//W3C//DTD XHTML 1.0 Frameset//EN"
One of the following public identifiers with a system identifier:
"-//W3C//DTD HTML 4.0 Transitional//EN"
"-//W3C//DTD HTML 4.0 Frameset//EN"
"-//W3C//DTD HTML 4.01 Transitional//EN"
"-//W3C//DTD HTML 4.01 Frameset//EN"
These Document Type Definitions (DTDs) are the only triggers for almost standards mode. Users cannot trigger almost standards mode through the user interface of their browsers because it is not listed as an option on the developer toolbar.