非常简单的UBB代码

效果图：

 <meta http-equiv="content-type" content="text/html;charset=utf8">
<?php 
  function getUbb($subject){
     $subject=preg_replace("/(\[)o_a(.*)(\])/iU", "<img src=\"http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a\\2.gif\"/>", $subject);//正则替换
     $subject=preg_replace("/\[b\](.*)\[\/b\]/iU", "<b>\\1</b>", $subject);
     $subject=preg_replace("/\[url\](.*)\[\/url\]/iU", "<a href=\"\\1\">\\1</a>", $subject);
     return $subject;
  }
  

 if ($_POST['sub']) {
 	echo getUbb($_POST['text']);
 	# code...
 }
 

?>

<hr>
<script>
	 function inserttag(open,close){
   var text=document.getElementById('content');
   text.focus();
   var s1=text.value;
   text.value =s1+open+close;
   return;
} 
 
</script>


<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a1.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a1","]");'>
<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a2.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a2","]");'>
<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a3.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a3","]");'>
<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a4.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a4","]");'>
<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a5.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a5","]");'>
<img src="http://images.cnblogs.com/cnblogs_com/perseverancevictory/570190/o_a6.gif" width="45" style="cursor:hand" onclick='inserttag("[o_a6","]");'>
<a href="javascript:void(0);" onclick='inserttag("[b]","[/b]");'>加粗</a>
<a href="javascript:void(0);" onclick='inserttag("[url]http://","[/url]");'>超链接</a>

 <form action="" method="post">
 	<textarea name="text" id="content" cols="40" rows="10"></textarea>
 	<input type="submit" name="sub" style="cursor:hand" value="提交">
 </form>