Selectors from level 4 to 1

CSS selectors level 4

Attribute case-sensitivity [attribute='value' i]
Dir pseudo-class :dir(ltr)
Lang pseudo-class :lang(en-*)
Matches-any pseudo-class :matches(s1, s2,)
Specificity-adjustment pseudo-class :something(s1, s2,)
Mutability pseudo-class :read-only / :read-write
Negation pseudo-class :not(s1, s2,)
Optionality pseudo-class :required / :optional
Placeholder pseudo-class :placeholder-shown
Validity pseudo-class :valid / :invalid
Range pseudo-class :in-range / :out-of-range
Grid-Structural pseudo-class :nth-col(n) / :nth-last-col(n)
Time-dimensional pseudo-class :current / :past / :future

CSS selectors level 3

Attribute [foo^='bar'] / [foo$='bar'] / [foo*='bar']
Enabled and Disabled pseudo-class :enabled / :disabled
Structural pseudo-class :root / :empty / :last-child / :only-child / :first-of-type / :last-of-type / :only-of-type / :nth-child(n) / :nth-last-child(n) / :nth-of-type(n) / :nth-last-of-type(n)

CSS selectors level 2

Lang pseudo-class :lang(en)
User action pseudo-class :hover / :focus
Attribute [foobar] / [attribute='value'] / [foo~='bar'] / [foo|='en']

CSS selectors level 1

Information are based on the CSS selectors level 4 - W3C Editors Draft from .