getElementsBySelector

代码说明：

  document.getElementsBySelector(selector) - returns an array of element objects from the current document matching the CSS selector. Selectors can contain element names, class names and ids and can be nested. For example: elements = document.getElementsBySelect( div#main p a.external ) Will return an array of all a elements with external in their class attribute that are contained inside p elements that are contained inside the div element which has id= main