The difference between Full Standard, Almost Standard, and Quirks Mode lies in how web browsers render web pages based on the HTML and CSS specifications they follow.
Full Standards Mode
In Full Standards Mode, the browser attempts to render the web page according to the strictest interpretation of the HTML and CSS specifications set by the World Wide Web Consortium (W3C). This mode is triggered by using a proper DOCTYPE at the beginning of the HTML document, such as <!DOCTYPE html>. This mode ensures that the page is displayed with the highest compliance to current web standards, which helps maintain consistency across different browsers and devices[3][5].
Almost Standards Mode
Almost Standards Mode, also known as Limited Quirks Mode, is very similar to Full Standards Mode with a few exceptions. The primary difference is in the way certain layout features are handled, particularly the vertical sizing of table cells. In this mode, the browser renders the page almost fully compliant with the standards, except for a small number of quirks that are maintained for backward compatibility. This mode is triggered by specific older DOCTYPEs that are almost standards-compliant but not quite[4].
Quirks Mode
Quirks Mode is a legacy rendering mode that allows browsers to emulate the non-standard behavior of old browsers like Netscape Navigator 4 and Internet Explorer 5. This mode is typically triggered when a DOCTYPE is omitted or when an outdated or incomplete DOCTYPE is used. In Quirks Mode, the browser uses a "best-guess" approach to interpre...
