Attribute selectors allow you to use the attributes that an element carries in the selector.
<p id="important" class="XHTML attributes">You must place all attributes in double quotes.</p>
paragraph[id] matches an element called paragraph carrying an attribute called id
paragraph[id="important"] matches an element called paragraph carrying an attribute called id whose value is important
paragraph[class~="XHTML"] matches an element called paragraph carrying an attribute called class, whose value is a list of space-separated words, one of which is exactly the same as XHTML
paragraph[class|="XHT"] matches an element called paragraph carrying an attribute called class whose value begins with XHT
