(PHP 5, PHP 7)
DOMDocument::createProcessingInstruction — Creates new PI node
$target
   [, string $data
  ] )This function creates a new instance of class DOMProcessingInstruction. This node will not show up in the document unless it is inserted with (e.g.) DOMNode::appendChild().
targetThe target of the processing instruction.
dataThe content of the processing instruction.
   The new DOMProcessingInstruction or FALSE if an error occurred.
  
DOM_INVALID_CHARACTER_ERR
       Raised if target contains an invalid character.