[1] Synchronized Multimedia Integration Language (6/15/1998, 7:11:22 PM 版) http://www.w3.org/TR/1998/REC-smil-19980615/#switch
[4] Document Structure – SVG 1.1 (Second Edition) ( (8/10/2011, 3:35:27 AM 版)) http://www.w3.org/TR/2011/REC-SVG11-20110816/struct.html#ConditionalProcessing
[2] systemLanguage
systemLanguage
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