Provide 4 functions which crypt e-mail address with javascript in order to not be captured by spammers robots.

• antispam_email_tag($emailaddress, $content) : generate an e-mail link_tag (mailto) encrypted in javascript

• antispam_js_encrypt($content) : encrypt in javascript some text

• antispam_auto_link_email_addresses($text) : Turns all email addresses into clickable links. Email links are encrypted.

• antispam_email_in_html($html) : Encrypt all e-mail link in HTML

  [php]

  function antispam_email_tag($emailaddress, $content=null, $options = array())
    {
      $options = _parse_attributes($options);
      $options['href'] = 'mailto:'.$emailaddress;
      if($content===null) $content=$emailaddress; 
      return antispam_js_encrypt(content_tag('a',$content,$options),rand(-8,5));
    }
   

  [php]

  function antispam_js_encrypt($content,$chr_adjust=-1)
    {
      $encoded_content='';
      for ($n = 0; $n < strlen($content); $n++)
      {
        $encoded_content .= dechex(ord(substr($content,$n,1))+ $chr_adjust) ; // + $chr_adjust
      }
   
      $rdm_function_name = '';
      while(strlen($rdm_function_name)<8)
      {
        $tmp = rand ( 65, 122);
        if($tmp > 96 || $tmp < 91 ) $rdm_function_name .= chr($tmp);
      }
   
      $js_function='function '.$rdm_function_name."(e) { for (i = 0; i <= e.length; i+=2) { document.write(String.fromCharCode((parseInt((('0x') + e.substring(i,i+2)),16)) - (".$chr_adjust.")));}}";
   
      return "<script>".$js_function."\n".$rdm_function_name."('" .$encoded_content. "');</script>";
    }
   

  [php]

  function antispam_auto_link_email_addresses($text)
    {
      $found=true; $offset=0;
      while($found)
      {
          $found=preg_match('/[\w\.!#\$%\-+.]+@[A-Za-z0-9\-]+\.[A-Za-z0-9\-]+/',$text,$matches, PREG_OFFSET_CAPTURE,$offset);
        if ($found)
        {
          $antispam_email_link=antispam_email_tag($matches[0][0]);
          $text=substr_replace ($text,$antispam_email_link,$matches[0][1],strlen($matches[0][0]));
          $offset=$matches[0][1]+strlen($antispam_email_link);
        }
      }
      return $text;
    }
   

  [php]

  function antispam_email_in_html($html)
    {
    $regex = '#<([aA])(\s)*(href|HREF)(\s)*=(\s)*[\"|\'](mailto:|MAILTO:)(.*?)[\"|\'](.*?)>(.*?)</\1>#is'; 
   
      $found=true; $offset=0;
      while($found)
      {
        $found=preg_match($regex,$html,$matches, PREG_OFFSET_CAPTURE,$offset);
        if ($found)
        {
          $antispam_email_link=antispam_email_tag($matches[7][0],$matches[9][0]);
          $html=substr_replace ($html,$antispam_email_link,$matches[0][1],strlen($matches[0][0]));
          $offset=$matches[0][1]+strlen($antispam_email_link);
        }
      }
      return $html;
    }