(PHP 5, PHP 7, PHP 8)
DOMElement::getElementsByTagName — Gets elements by tagname
   This function returns a new instance of the class
   DOMNodeList of all descendant elements with a
   given tag qualifiedName, in the order in which they are
   encountered in a preorder traversal of this element tree. 
  
qualifiedName
       The 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.