TYPO3 Core

$this->constructMixed($boundary);

} elseif ($this->theParts['html']['content']) {

// Generate plain/HTML mail

$this->add_header(' boundary="' . $boundary . '"');

$this->add_message('This is a multi-part message in MIME format.' . "\n");

$this->constructHTML($boundary);

if ($this->theParts['html']['content']) {

// HTML and plain is added

$newBoundary = $this->getBoundary();

$this->add_message(' boundary="' . $newBoundary . '"');

$this->add_message('');

$this->constructHTML($newBoundary);