替换所有空格为空
$contents=" abc ";
$contents=preg_replace('/\s+/','',$contents);
//结果$contents="abc";
替换所有换行符
$contents = str_replace(array("\r\n", "\r", "\n"), "", $contents);
匹配任意字符除了换行(.*?)
preg_match_all('/<h1 class="ff f20 fb fl">(.*?)<\/h1>/',$contents, $out, PREG_SET_ORDER);