(PHP 5, PHP 7)
DOMElement::getElementsByTagName — Gets elements by tagname
   This function returns a new instance of the class
   DOMNodeList of all descendant elements with a
   given tag name, in the order in which they are
   encountered in a preorder traversal of this element tree. 
  
nameThe tag name. Use * to return all elements within the element tree.
This function returns a new instance of the class DOMNodeList of all matched elements.