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Meta tag X-UA-Compatible

Meta tag X-UA-Compatible controls the mode of displaying pages in IE8 + browsers

Syntax

<meta http-equiv="X-UA-Compatible" content="..." />

Values ​​for IE8 +

Tag value IE8 + mode description Mode Code Name
IE = 5 Displaying content in IE5 compatibility mode, displays pages as IE5.5 does, regardless of whether the page contains a <! DOCTYPE> directive Quirks mode (compatibility mode)
IE = 7 Displaying content in standard IE7 mode, displays pages as IE7 does, regardless of whether the page contains a <! DOCTYPE> directive IE 7 Standards mode (standard IE7 mode)
IE = EmulateIE7 forces IE to use the <! DOCTYPE> directive to specify how to display content. Standard mode directives are displayed in IE7 standard mode, and compatibility mode directives are displayed in IE5.5 mode (Quirks). IE 7 Emulation mode (IE7 emulation mode)
IE = 8 Displaying content in IE8 standard mode, displays pages as IE8 does, regardless of whether the page contains a <! DOCTYPE> directive IE 8 Standards mode (standard IE8 mode)
IE = EmulateIE8 forces IE to use the <! DOCTYPE> directive to specify how to display content. Standard mode directives are displayed in IE8 standard mode, and compatibility mode directives are displayed in IE5.5 mode (Quirks). IE 8 Emulation mode (IE8 emulation mode)
IE = edge always uses the latest available standard display mode regardless of <! DOCTYPE>. Edge mode (last mode)

Values ​​added in IE9

Tag value IE9 mode description Mode Code Name
IE = 9 Displaying content in standard IE9 mode, displays pages as IE9 does, regardless of whether the page contains a <! DOCTYPE> directive IE 9 Standards mode (standard IE9 mode)
IE = EmulateIE9 forces IE to use the <! DOCTYPE> directive to specify how to display content. Standard mode directives are displayed in IE9 standard mode, and compatibility mode directives are displayed in IE5.5 mode (Quirks). IE 9 Emulation mode (IE9 emulation mode)

If directive not specified, IE behaves as if a compatibility mode directive (Quirks DOCTYPE) is specified.

Example

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

The tag must be in the head section of the page before all other elements, except for the title and other meta-elements. Otherwise, it is ignored!