Selectors Level 4

Ideas to consider

• Current URL Selector (with directory levels)
• IDREF combinators: /attr/ syntax, friend(attribute, selector) syntax
• relationship selectors, e.g.:
  • to select cells in a column: col.foo // td
  • to select labels applying to an input control: input // label
  • to select map elements associated with an image: img // map
• pseudo-attribute selectors, e.g. to select cells that are in the second column of a table: [#column=2]
• numeric attribute selectors, e.g. [height>2], [count<=5], [balance<0], [#row>1]
• :rtl and :ltr pseudo-classes (based on source dir attributes) (or maybe :dir(rtl|ltr)?)
• ability to choose subject in the selector (alternative syntax) (discussion of syntaxes)
• :matches() pseudo-class (alternate)
• ::quote-start and ::quote-end, to match characters with the Quotation_Mark property that are direct children of the element and that are immediately inside the start and end (respectively) of the element, ignoring White_Space characters. (This would help a lot with <q> in HTML5.)
• dynamic values selector and/or a pseudo-class for placeholder text
• ::window pseudo-element
• limited descendant combinator more info
• Better definition of :first-letter http://lists.w3.org/Archives/Public/www-style/2010Aug/0063.html + note in Selectors L3
• :nth-match(<selector>, <an+b>)