Compatibility Mode Test

Doctype is <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML Strict Level 2//EN">.

The quirks stylesheet is NOT applied.
The quirks stylesheet is applied.

You can't see this.

The inline box model shows you are in full standards mode.
The inline box model shows you are in quirks mode or almost standards mode.

You can't see this.

The CSS stylesheet code is in standards mode.

The CSS stylesheet code is in quirks mode.

Comment parsing is in quirks standards mode.

The DOM says we are in mode.