PHP多个连续空格回车替换为一个，怎么写更简短

<br><br>function re($content)<br>{<br>    /* return preg_replace('/(<br\s*\ ?="">){3,}|( ){3,}/i'),'\\1',$content); */ //错误！<br>    /* return preg_replace('/(<br\s*\ ?="">| ){3,}/i'),'\\1',$content); */ //错误！<br>    return preg_replace(array('/(<br\s*\ ?="">){3,}/i','/( ){3,}/i'),'\\1',$content);<br>}<br><br><br>//test<br>$content = '1111    <br><br><br><br>@@@<br><br><br><br>aaaaM<br><br>';<br>echo re($content);<br>exit();<br></br\s*\></br\s*\></br\s*\>