/* has attribute */
div[class] { }

/* is attribute */
div[class="foo"] { }

/* contains single word */
div[class="foo"] { }

/* starts with single word */
div[class|="foo"] { }

/* starts with */
div[class^="foo"] { }

/* ends with */
div[class$="foo"] { }

/* contains */
div[class*="foo"] { }