定义文件：\source\function\function_editor.php

function html2bbcode($text) {
	$text = strip_tags($text, '<table><tr><td><b><strong><i><em><u><a><div><span><p><strike><blockquote><ol><ul><li><font><img><br><br/><h1><h2><h3><h4><h5><h6><script>');
 
 
	if(ismozilla()) {
		$text = preg_replace("/(?<!<br>|<br \/>|\r)(\r\n|\n|\r)/", ' ', $text);
	}
 
 
	$pregfind = array(
		"/<script.*>.*<\/script>/siU",
		'/on(mousewheel|mouseover|click|load|onload|submit|focus|blur)="[^"]*"/i',
		"/(\r\n|\n|\r)/",
		"/<table([^>]*(width|background|background-color|bgcolor)[^>]*)>/siUe",
		"/<table.*>/siU",
		"/<tr.*>/siU",
		"/<td>/i",
		"/<td(.+)>/siUe",
		"/<\/td>/i",
		"/<\/tr>/i",
		"/<\/table>/i",
		'/<h([0-9]+)[^>]*>/siUe',
		'/<\/h([0-9]+)>/siU',
		"/<img[^>]+smilieid=\"(\d+)\".*>/esiU",
		"/<img([^>]*src[^>]*)>/eiU",
		"/<a\s+?name=.+?\".\">(.+?)<\/a>/is",
		"/<br.*>/siU",
		"/<span\s+?style=\"float:\s+(left|right);\">(.+?)<\/span>/is",
	);
	$pregreplace = array(
		'',
		'',
		'',
		"tabletag('\\1')",
		'[table]',
		'[tr]',
		'[td]',
		"tdtag('\\1')",
		'[/td]',
		'[/tr]',
		'[/table]',
		"\"[size=\".(7 - \\1).\"]\"",
		"[/size]\n\n",
		"smileycode('\\1')",
		"imgtag('\\1')",
		'\1',
		"\n",
		"[float=\\1]\\2[/float]",
	);
	$text = preg_replace($pregfind, $pregreplace, $text);
 
 
	$text = recursion('b', $text, 'simpletag', 'b');
	$text = recursion('strong', $text, 'simpletag', 'b');
	$text = recursion('i', $text, 'simpletag', 'i');
	$text = recursion('em', $text, 'simpletag', 'i');
	$text = recursion('u', $text, 'simpletag', 'u');
	$text = recursion('a', $text, 'atag');
	$text = recursion('font', $text, 'fonttag');
	$text = recursion('blockquote', $text, 'simpletag', 'indent');
	$text = recursion('ol', $text, 'listtag');
	$text = recursion('ul', $text, 'listtag');
	$text = recursion('div', $text, 'divtag');
	$text = recursion('span', $text, 'spantag');
	$text = recursion('p', $text, 'ptag');
 
 
	$pregfind = array("/(?<!\r|\n|^)\[(\/list|list|\*)\]/", "/<li>(.*)((?=<li>)|<\/li>)/iU", "/<p.*>/iU", "/<p><\/p>/i", "/(<a>|<\/a>|<\/li>)/is", "/<\/?(A|LI|FONT|DIV|SPAN)>/siU", "/\[url[^\]]*\]\[\/url\]/i", "/\[url=javascript:[^\]]*\](.+?)\[\/url\]/is");
	$pregreplace = array("\n[\\1]", "\\1\n", "\n", '', '', '', '', "\\1");
	$text = preg_replace($pregfind, $pregreplace, $text);
 
 
	$strfind = array(' ', '<', '>', '&');
	$strreplace = array(' ', '<', '>', '&');
	$text = str_replace($strfind, $strreplace, $text);
 
 
	return dhtmlspecialchars(trim($text));
}

示范：

require_once libfile('function/editor');
$html='<strong>这里是加粗文本</strong>';
$bbcode = html2bbcode($html);
echo $bbcode;
//输出：[b]这里是加粗文本[/b]