来源：Richard Heyes
  
   <?php
  class html_mime_mail{
  
  var $headers;
  var $body;
  var $multipart;
  var $mime;
  var $html;
  var $html_text;
  var $html_images = array();
  var $cids = array();
  var $do_html;
  var $parts = array();
  
  /***************************************
  ** Constructor function. Sets the headers
  ** if supplied.
  ***************************************/
  function html_mime_mail($headers = ''){
  $this->headers = $headers;
  }
  
  /***************************************
  ** Adds a html part to the mail.
  ** Also replaces image names with
  ** content-id's.
  ***************************************/
  function add_html($html, $text){
  $this->do_html = 1;
  $this->html = $html;
  $this->html_text = $text;
  if(is_array($this->html_images) AND count($this->html_images) > 0){
  for($i=0; $i<count($this->html_images); $i++){
  $this->html = ereg_replace($this->html_images[$i]['name'], 'cid:'.$this->html_images[$i]['cid'], $this->html);
  }
  }
  }
  
  /***************************************
  ** Builds html part of email.
  ***************************************/
  function build_html($orig_boundary){
  $sec_boundary = '=_'.md5(uniqid(time()));
  $thr_boundary = '=_'.md5(uniqid(time()));
  
  if(!is_array($this->html_images)){
  $this->multipart.= '--'.$orig_boundary."rn";
  $this->multipart.= 'Content-Type: multipart/alternative; boundary="'.$sec_boundary.""rnrnrn";
  
  $this->multipart.= '--'.$sec_boundary."rn";
  $this->multipart.= 'Content-Type: text/plain'."rn";
  $this->multipart.= 'Content-Transfer-Encoding: 7bit'."rnrn";
  $this->multipart.= $this->html_text."rnrn";
  
  $this->multipart.= '--'.$sec_boundary."rn";
  $this->multipart.= 'Content-Type: text/html'."rn";
  $this->multipart.= 'Content-Transfer-Encoding: 7bit'."rnrn";
  $this->multipart.= $this->html."rnrn";
  $this->multipart.= '--'.$sec_boundary."--rnrn";
  }else{
  $this->multipart.= '--'.$orig_boundary."rn";
  $this->multipart.= 'Content-Type: multipart/related; boundary="'.$sec_boundary.""rnrnrn";
  
  $this->multipart.= '--'.$sec_boundary."rn";
  $this->multipart.= 'Content-Type: multipart/alternative; boundary="'.$thr_boundary.""rnrnrn";
  
  $this->multipart.= '--'.$thr_boundary."rn";
  $this->multipart.= 'Content-Type: text/plain'."rn";
  $this->multipart.= 'Content-Transfer-Encoding: 7bit'."rnrn";
  $this->multipart.= $this->html_text."rnrn";
  
  $this->multipart.= '--'.$thr_boundary."rn";
  $this->multipart.= 'Content-Type: text/html'."rn";
  $this->multipart.= 'Content-Transfer-Encoding: 7bit'."rnrn";
  $this->multipart.= $this->html."rnrn";
  $this->multipart.= '--'.$thr_boundary."--rnrn";
  
  for($i=0; $i<count($this->html_images); $i++){
  $this->multipart.= '--'.$sec_boundary."rn";
  $this->build_html_image($i);
  }
  
  $this->multipart.= "--