Snippet. PHP. Function to convert BBCode to HTML

Working with BBCode is a everyday job for PHP developers. BBCode is convenient as it allows regular users to format text using easy to understand and user friendly set of rules.

The function bbcode_to_html($bbtext) takes a bbcode formatted text and returns text formatted with HTML tags, which can be displayed on a web page.

The function is extended to include user-friendly and more readable version of BBCode tags, like [heading1], [paragraph], [bold], [italic], [underline], [unordered_list], [list_item], [newline], etc. However, it also includes their shortcut equivalents, like [h1], [p], [b], [i], [u], [ul], [li], [br], etc., which are more convenient for tech-savvy users.

//======================== START OF FUNCTION ==========================//
// FUNCTION: bbcode_to_html                                            //
//=====================================================================//
function bbcode_to_html($bbtext){
  $bbtags = array(
    '[heading1]' => '<h1>','[/heading1]' => '</h1>',
    '[heading2]' => '<h2>','[/heading2]' => '</h2>',
    '[heading3]' => '<h3>','[/heading3]' => '</h3>',
    '[h1]' => '<h1>','[/h1]' => '</h1>',
    '[h2]' => '<h2>','[/h2]' => '</h2>',
    '[h3]' => '<h3>','[/h3]' => '</h3>',

    '[paragraph]' => '<p>','[/paragraph]' => '</p>',
    '[para]' => '<p>','[/para]' => '</p>',
    '[p]' => '<p>','[/p]' => '</p>',
    '[left]' => '<p style="text-align:left;">','[/left]' => '</p>',
    '[right]' => '<p style="text-align:right;">','[/right]' => '</p>',
    '[center]' => '<p style="text-align:center;">','[/center]' => '</p>',
    '[justify]' => '<p style="text-align:justify;">','[/justify]' => '</p>',

    '[bold]' => '<span style="font-weight:bold;">','[/bold]' => '</span>',
    '[italic]' => '<span style="font-weight:bold;">','[/italic]' => '</span>',
    '[underline]' => '<span style="text-decoration:underline;">','[/underline]' => '</span>',
    '[b]' => '<span style="font-weight:bold;">','[/b]' => '</span>',
    '[i]' => '<span style="font-weight:bold;">','[/i]' => '</span>',
    '[u]' => '<span style="text-decoration:underline;">','[/u]' => '</span>',
    '[break]' => '<br>',
    '[br]' => '<br>',
    '[newline]' => '<br>',
    '[nl]' => '<br>',
    
    '[unordered_list]' => '<ul>','[/unordered_list]' => '</ul>',
    '[list]' => '<ul>','[/list]' => '</ul>',
    '[ul]' => '<ul>','[/ul]' => '</ul>',
	
    '[ordered_list]' => '<ol>','[/ordered_list]' => '</ol>',
    '[ol]' => '<ol>','[/ol]' => '</ol>',
    '[list_item]' => '<li>','[/list_item]' => '</li>',
    '[li]' => '<li>','[/li]' => '</li>',
	    
    '[*]' => '<li>','[/*]' => '</li>',
    '[code]' => '<code>','[/code]' => '</code>',
    '[preformatted]' => '<pre>','[/preformatted]' => '</pre>',
    '[pre]' => '<pre>','[/pre]' => '</pre>',		    
  );
	
  $bbtext = str_ireplace(array_keys($bbtags), array_values($bbtags), $bbtext);

  $bbextended = array(
    "/\[url](.*?)\[\/url]/i" => "<a href=\"http://$1\" title=\"$1\">$1</a>",
    "/\[url=(.*?)\](.*?)\[\/url\]/i" => "<a href=\"$1\" title=\"$1\">$2</a>",
    "/\[email=(.*?)\](.*?)\[\/email\]/i" => "<a href=\"mailto:$1\">$2</a>",
    "/\[mail=(.*?)\](.*?)\[\/mail\]/i" => "<a href=\"mailto:$1\">$2</a>",
    "/\[img\]([^[]*)\[\/img\]/i" => "<img src=\"$1\" alt=\" \" />",
    "/\[image\]([^[]*)\[\/image\]/i" => "<img src=\"$1\" alt=\" \" />",
    "/\[image_left\]([^[]*)\[\/image_left\]/i" => "<img src=\"$1\" alt=\" \" class=\"img_left\" />",
    "/\[image_right\]([^[]*)\[\/image_right\]/i" => "<img src=\"$1\" alt=\" \" class=\"img_right\" />",
  );

  foreach($bbextended as $match=>$replacement){
    $bbtext = preg_replace($match, $replacement, $bbtext);
  }
  return $bbtext;
}
//=====================================================================//
//  FUNCTION: bbcode_to_html                                           //
//========================= END OF FUNCTION ===========================//

Example

$bbtext = file_get_contents('bbcode_text.txt');

$html = bbcode_to_html($bbtext);

echo $html;

Updated on: 06 Nov 2025