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Text of the page (random words):
main page contents current events random article about wikipedia contact us contribute help learn to edit community portal recent changes upload file special pages search search appearance donate create account log in personal tools donate create account log in contents move to sidebar hide top 1 overview 2 mode differences and examples toggle mode differences and examples subsection 2 1 limited quirks mode 3 triggering different rendering modes toggle triggering different rendering modes subsection 3 1 comparison of document types 3 2 mode verification 4 references 5 external links toggle the table of contents quirks mode 15 languages العربية deutsch esperanto español italiano 한국어 nederlands polski русский සිංහල српски srpski svenska українська 粵語 中文 edit links article talk english read edit view history tools tools move to sidebar hide actions read edit view history general what links here related changes upload file permanent link page information cite this page get shortened url switch to legacy parser print export download as pdf printable version in other projects wikidata item appearance move to sidebar hide from wikipedia the free encyclopedia technique used by web browsers to maintain backwards compatibility with older web pages html html and variants dynamic html html5 xhtml basic mobile profile html elements and attributes html element article audio blink canvas div and span marquee meta video html attribute alt attribute html frame editing html editor text editor character encodings and language character encodings character entity references named characters unicode language code document and browser technology document object model browser object model style sheets css font family web colors quirks mode web storage rendering engine client side scripting and apis javascript webcl htmx web3d technology web3d webgl webgpu webxr standardizations w3c validator whatwg mdn web docs web platform comparisons document markup languages comparison of browser engines v t e in computing quirks mode is an approach used by web browsers to maintain backward compatibility with web pages designed for old web browsers instead of strictly complying with web standards in standards mode this behavior has since been codified so what was previously standards mode is now referred to as simply no quirks mode overview edit the structure and appearance of a web page is described by a combination of two standardized languages html a markup language designed for web use which describes the structure and content of the page and css a generalized stylesheet language which specifies how the page should be rendered in various media visual styles for screen display print styles to use when printing the page aural styles to use when the page is read aloud by a screen reader etc however most older web browsers either did not fully implement the specifications for these languages or were developed prior to the finalization of the specifications microsoft internet explorer version 5 0 for the macintosh platform released in 2000 was the first major web browser with full support for css level 1 for example 1 as a result many older web pages were constructed to rely upon the older browsers incomplete or incorrect implementations and will only render as intended when handled by such a browser support for standardized html and css in major web browsers has increased significantly but the large body of legacy documents which rely on the quirks of older browsers represents an obstacle for browser developers who wish to improve their support for standardized html and css but also wish to maintain backward compatibility with older non standardized pages additionally many new web pages continue to be created in the older fashion since the compatibility workarounds introduced by browser developers mean that an understanding of standardized methods is not strictly necessary to maintain compatibility with the greatest possible number of web pages modern web browsers are generally developed with multiple rendering modes in no quirks mode pages are rendered according to the html and css specifications while in quirks mode attempts are made to emulate the behavior of older browsers some browsers those based on mozilla s gecko rendering engine or internet explorer 8 in strict mode for example also use an almost standards mode which attempts to compromise between the two implementing one quirk for table cell sizing while otherwise conforming to the specifications 2 mode differences and examples edit one prominent difference between quirks and no quirks modes is the handling of the css internet explorer box model bug before version 6 internet explorer used an algorithm for determining the width of an element s box which conflicted with the algorithm detailed in the css specification and due to internet explorer s popularity many pages were created which relied upon this non standard algorithm as of version 6 internet explorer uses the css specification s algorithm when rendering in no quirks mode and uses the previous non standard algorithm when rendering in quirks mode citation needed another notable difference is the vertical alignment of certain types of inline content many older browsers aligned images to the bottom border of their containing box although the css specification requires that they be aligned to the baseline of the text within the box in no quirks mode gecko based browsers will align to the baseline and in quirks mode they will align to the bottom 3 additionally many older browsers did not implement inheritance of font styles within tables as a result font styles had to be specified once for the document as a whole and again for the table even though the css specification requires that font styling be inherited into the table if the font sizes are specified using relative units a standards compliant browser would inherit the base font size then apply the relative font size within the table for example a page which declared a base font size of 80 and a table font size of 80 to ensure a size of 80 in browsers which do not properly inherit font sizes would in a standards compliant browser display tables with a font size of 64 80 of 80 as a result browsers typically do not inherit font sizes into tables in quirks mode 4 limited quirks mode edit a third compatibility mode known as limited quirks mode previously almost standards mode or strict mode which maintains the traditional vertical sizing of table cells according to the css2 specification has been implemented in these browsers safari opera 7 5 and later all gecko based browsers since 1 0 1 such as firefox and internet explorer 8 2 almost standards mode rendering matches standards mode in all details except for one the layout of images inside table cells is handled the same way quirks mode operates instead which is fairly consistent with legacy browsers such as internet explorer 7 and earlier this means that sliced images in tables layouts are less likely to fall apart in browsers when in either quirks or almost standards mode rather than standards mode 5 triggering different rendering modes edit most often browsers determine which rendering mode to use based on the presence of a document type declaration in the page if a full doctype is present the browser will use no quirks mode and if it is absent the browser will use quirks mode for example a web page which began with the following doctype would trigger no quirks mode doctype html public w3c dtd html 4 01 en http www w3 org tr html4 strict dtd the following doctype is syntactically invalid containing the public identifier keyword public but no public identifier indicating the name of the version of html in use and no system identifier url of an html document type definition this would trigger quirks mode doctype html public additionally a web page which does not include a doctype at all will render in quirks mode one notable exception to this is microsoft s internet explorer 6 browser which will render a page in quirks mode if the doctype is preceded by an xml prolog regardless of whether a full doctype is specified thus an xhtml page which begins with the following code would be rendered in quirks mode by ie 6 xml version 1 0 encoding utf 8 doctype html public w3c dtd xhtml 1 0 strict en http www w3 org tr xhtml1 dtd xhtml1 strict dtd the above is useful to an extent as it can be used to trigger quirks mode only in ie 6 quirks mode in any version of ie will also be triggered if anything precedes the doctype for example if a hypertext document contains a comment space or any tag before the doctype declaration ie will use quirks mode this comment will put ie 6 7 8 and 9 in quirks mode doctype html public w3c dtd html 4 01 en http www w3 org tr html4 strict dtd the problem with the xml declaration was fixed in version 7 of internet explorer in which the xml prolog is simply ignored 6 however for maximum compatibility with existing and older web browsers the world wide web consortium which maintains the xhtml specification suggests that authors of xhtml documents could consider omitting the xml declaration 7 comparison of document types edit henri sivonen compiled a list of various document types and how they are treated in the most common browsers showing whether pages are rendered in q uirks s tandards or a lmost standards mode the criterion used for almost standards mode is non standard table cell height rendering this table applies to content served with the content type text html content served with the content type application xhtml xml is rendered in standards mode in chrome firefox internet explorer 9 safari and opera internet explorer 6 7 and 8 do not support content type application xhtml xml 2 doctype ns6 mozilla 0 9 5 1 0 ie 8 firefox chrome safari opera 7 5 netscape 7 mozilla 1 0 1 konq 3 5 html5 spec ie 7 opera 7 10 ie 6 opera 7 0 mac ie 5 konq 3 2 none html q q q q q q q html 2 doctype html public ietf dtd html 2 0 en q q q q q q q html 3 doctype html public ietf dtd html 3 0 en q q q q q q q html 3 2 doctype html public w3c dtd html 3 2 final en q q q q q q q html 4 01 strict with system identifier doctype html public w3c dtd html 4 01 en http www w3 org tr html4 strict dtd s s s a a a a without system identifier doctype html public w3c dtd html 4 01 en s s s a a q a transitional with system identifier doctype html public w3c dtd html 4 01 transitional en http www w3 org tr html4 loose dtd s s a a a a q without system identifier doctype html public w3c dtd html 4 01 transitional en q q q q q q q html5 doctype html q s s a a a xhtml basic with system identifier and without xml declaration doctype html public w3c dtd xhtml basic 1 0 en http www w3 org tr xhtml basic xhtml basic10 dtd s s s a a a a xhtml 1 0 strict with system identifier and xml declaration xml version 1 0 encoding utf 8 doctype html public w3c dtd xhtml 1 0 strict en http www w3 org tr xhtml1 dtd xhtml1 strict dtd s s s a q a q with system identifier and without an xml declaration doctype html public w3c dtd xhtml 1 0 strict en http www w3 org tr xhtml1 dtd xhtml1 strict dtd s s s a a a a without system identifier and without an xml declaration doctype html public w3c dtd xhtml 1 0 strict en s s s a a a transitional with system identifier and with xml declaration xml version 1 0 encoding utf 8 doctype html public w3c dtd xhtml 1 0 transitional en http www w3 org tr xhtml1 dtd xhtml1 transitional dtd s s a a q a q with system identifier and without an xml declaration doctype html public w3c dtd xhtml 1 0 transitional en http www w3 org tr xhtml1 dtd xhtml1 transitional dtd s s a a a a q without system identifier and without an xml declaration doctype html public w3c dtd xhtml 1 0 transitional en s s a a a a xhtml 1 1 with system identifier and an xml declaration xml version 1 0 encoding utf 8 doctype html public w3c dtd xhtml 1 1 en http www w3 org tr xhtml11 dtd xhtml11 dtd s s s a q a q with system identifier and without xml declaration doctype html public w3c dtd xhtml 1 1 en http www w3 org tr xhtml11 dtd xhtml11 dtd s s s a a a a doctype ns6 mozilla 0 9 5 1 0 ie 8 firefox chrome safari opera 7 5 netscape 7 mozilla 1 0 1 konq 3 5 html5 spec ie 7 opera 7 10 ie 6 opera 7 0 mac ie 5 konq 3 2 mode verification edit in most browsers the document object model extension document compatmode indicates the rendering mode for the current page in standards mode and almost standards mode document compatmode contains the value css1compat while in quirks mode it equals backcompat 8 additionally in mozilla firefox and opera the rendering mode in use for a given page is indicated on the page info informational box references edit cascading style sheets css browsers world wide web consortium 19 december 2001 retrieved 27 may 2007 1 2 3 sivonen henri activating browser modes with doctype retrieved 15 march 2011 images tables and mysterious gaps mozilla developer center archived from the original on 22 may 2017 retrieved 27 may 2007 fixing table inheritance in quirks mode mozilla developer center archived from the original on 3 march 2016 retrieved 27 may 2007 gecko s almost standards mode mozilla developer center archived from the original on 3 june 2004 retrieved 27 may 2007 wilson chris 15 august 2005 the xml prolog strict mode and xhtml in ie ieblog msdn retrieved 27 may 2007 html compatibility guidelines xhtml 1 0 the extensible hypertext markup language second edition world wide web consortium 1 august 2002 retrieved 14 february 2009 koch peter paul 2 february 2009 miscellaneous w3c dom compatibility html quirksmode retrieved 14 february 2009 external links edit quirks mode living standard the w3c markup validation service testing doctype handling in browser quirksmode org quirks mode and strict mode bookmarklet that reports the mode of a document eric meyer on css picking a rendering mode mdc explanation of mozilla s doctype sniffing archived 2016 10 13 at the wayback machine documentation for quirks mode in mozilla based browsers archived 2015 12 05 at the wayback machine opera software s explanation of quirks mode in their browser what happens in quirks mode retrieved from https en wikipedia org w index php title quirks_mode oldid 1301752159 category html hidden categories articles with short description short description matches wikidata all articles with unsourced statements articles with unsourced statements from june 2015 webarchive template wayback links this page was last edited on 21 july 2025 at 13 24 utc page was rendered with parsoid text is available under the creative commons attribution sharealike 4 0 license additional terms may apply by using this site you agree to the terms of use and privacy policy wikipedia is a registered trademark of the wikimedia foundation inc a non profit organization privacy policy about wikipedia disclaimers contact wikipedia legal safety contacts code of conduct developers statistics cookie statement 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