How does the browser behave if an incorrect DOCTYPE is specified?
Difficulty level
It sends an error report to the server.
The browser defaults to quirks mode.
The browser immediately closes the tab.
The page becomes unresponsive.
If an incorrect or outdated DOCTYPE is specified, most modern browsers will default to "quirks mode." In this mode, the browser tries to render the document by emulating the behavior of older browsers, which can result in unexpected visual discrepancies. While "quirks mode" allows older pages to be displayed more accurately, it's not a mode you want for modern web design since it doesn't adhere to current standards.