Browser parsing mode: Detailed explanation of usage of DOCTYPE declaration issues-HTML Tutorial-php.cn

Webpage production cnn6 article introduction: IE8 has 4 modes: IE5.5 weird mode, IE7 standard mode, IE8 almost standard mode, IE8 standard model.

Trigger standard mode

1. Add DOCTYPE statement, such as:

< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
< !DOCTYPE html>

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2. Set X-UA-Compatible trigger.

Trigger weird mode

1. No doctype statement, define old HTML version (below HTML4, such as 3.2)
2. Add XML statement, can be triggered under ie6

3. Add HTML between the XML declaration and the DOCTYPE of XHTML Comment, can be triggered under ie7
< !-- keep IE7 in quirks mode -->
< !DOCTYPE ...>
5, placed in front of

IE8 has 4 modes: IE5.5 weird mode, IE7 standard mode, IE8 almost standard mode, IE8 standard mode

The impact of X-UA-Compatible setting on IE8 mode:
1. Set X-UA-Compatible meta

IE=5, IE= 6 (any number between 5 and 6, such as 5.987654321): trigger IE5 weird mode (regardless of whether the page has DOCTYPE)
IE=7(7<= value<8): force IE7 standard (regardless of the page Whether there is DOCTYPE)
IE=EmulateIE7: Follow DOCTYPE (with DOCTYPE-IE7 standard; no DOCTYPE-IE5 weird mode)
IE=EmulateIE8: Follow DOCTYPE (DOCTYPE-IE8 almost standard mode (or IE8 standard mode); No DOCTYPE-IE5 weird mode)
IE=8, IE=Edge, IE=99, IE=9.9 (greater than or equal to 8): With doctype-use almost standard mode, or IE8 standard; without doctype-IE8 standard.
No X-UA-Compatible, IE=IE8, IE=IE7, IE=a, write X-UA-Compatible after the or