Quirks mode

The quirks mode (from English " quirk " = character, Macke ) is a compatibility mode in different programs, the errors of previous versions or similar programs simulated.

Quirks mode in browsers

The main quirks modes can be found in the current Web browsers. This is to ensure backward compatibility with sites that use outdated or invalid HTML or CSS code. In this case, inter alia, representation error of older browser versions are simulated, so that the layout of this website is not destroyed. For example, simulating the Internet Explorer 9 in quirks mode Internet Explorer 5 need the quirks mode is mainly because only a few sites adhere to the W3C standards: Many pages are designed for Internet Explorer or an older Netscape Navigator. These browsers interpret the standards partially incorrect. Modern browsers that support the latest standards, would these pages is correct, but not display as intended. Due to quirks mode, it is often possible to display these actually failed pages.

All modern browsers set the display mode from after the Document Type Definition ( DOCTYPE ) in the HTML source code. If there is no doctype specified, the quirks mode will be used.

Among other cause following document type definitions that a page using standards-compliant mode ( strict ) is displayed:

< DOCTYPE html PUBLIC " - / / W3C / / DTD HTML 4.01 / / EN " " http://www.w3.org/TR/html4/strict.dtd " > < - HTML 4.01 with URI -> < DOCTYPE html PUBLIC "- / / W3C / / DTD HTML 4.01 / / EN " > < - HTML 4.01 without URI -> < - HTML General (version 5, but backwards compatible with old browsers) -> Microsoft's Internet Explorer does not recognize version 6 with strictly designed according to the rules of the W3C XHTML documents whose document type definition and switches to quirks mode. Such documents included in the first line of the XML declaration with elementary information on the character set used, instead, as erroneously expected by the browser, the document type definition. This may be displayed incorrectly these documents.

The quirks mode is the counterpart of the standard -mapped mode. Some browsers have also a Almost default mode, which is essentially based on the standards, but simulates some errors with particularly serious consequences.

Quirks modes in other programs

The Turbo Assembler had a quirks mode, were simulated in the bow of the popular MASM from Microsoft.