HTML/CSS Case Sensitivity

By Xah Lee. Date: . Last updated: .

Case sensitivity:

HTML tag names
Case insensitive. <div> = <Div>
HTML attribute name
Case insensitive. class= = Class=.
HTML attribute values
Case sensitive. class="A"class="a".
XML/XHTML tag name
Case sensitive. Must be lowercase.
XML/XHTML attribute name
Case sensitive. class=Class=
XML/XHTML attribute values
Case sensitive. class="A"class="a".
CSS selectors for html tag names
Case insensitive. div.x = Div.x
CSS selectors for html attribute names
Case insensitive. div[target] = div[TARget]
CSS selectors for html attribute values
Case sensitive. div.adiv.A

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