/**
 * 格式化内容
 * @param string $content 内容最好统一用utf-8编码
 * @return string
 * !本函数需要开启tidy扩展
 */
function removeFormat($content) {
 $replaces = array (
   "/<font.*?>/i" => '',
   "/<\/font>/i" => '',
   "/<strong>/i" => '',
   "/<\/strong>/i" => '',
   "/<span.*?>/i" => '',
   "/<\/span>/i" => '',
   "/<div.*?>/i" => "<p>",
   "/<\/div>/i" => "</p>",
   "/<!--<.*?>*-->/i"=>'',
   /* "/<table.*?>/i" => '',//遇到有表格的内容就不要启用
   "/<\/table>/i" => '',
   "/<tbody.*?>/i" => '',
   "/<\/tbody>/i" => '',
   "/<tr.*?>/i" => '<p>',
   "/<\/tr>/i" => '</p>',
   "/<td.*?>/i" => '', */
   "/style=.+?['|\"]/i" => '',
   "/class=.+?['|\"]/i" => '',
   "/id=.+?['|\"]/i"=>'',
   "/lang=.+?['|\"]/i"=>'',
   //"/width=.+?['|\"]/i"=>'',//不好控制注释掉
   //"/height=.+?['|\"]/i"=>'',
   "/border=.+?['|\"]/i"=>'',
   "/face=.+?['|\"]/i"=>'',
   "/<br.*?>[　]*/i" => "</p><p>",
   "/<iframe.*?>.*<\/iframe>/i" => '',
   "/ /i" => ' ',//空格替换掉
   "/<p.*?>[ |\x{3000}|\r\n]*/ui" => '<p>    ',//替换半角、全角空格，换行符，用 排除写入数据库时产生的编码问题

 );
 $config = array(
         //'indent' => TRUE, //是否缩进 
                'output-html' => TRUE,//是否是输出xhtml 
                'show-body-only'=>TRUE,//是否只获得到body 
               'wrap' => 0
    );
 $content = tidy_repair_string($content, $config, 'utf8');//先利用php自带的tidy类库修复html标签，不然替换的时候容易出现各种诡异的情况
 $content = trim($content);
 foreach ( $replaces as $k => $v ) {
  $content = preg_replace ( $k, $v, $content );
 }

 if(strpos($content,'<p>')>6)//部分内容开头可能缺失<p>标签
  $content = '<p>    '.$content;

 $content = tidy_repair_string($content, $config, 'utf8');//再修复一次，可以去除html空标签
 $content = trim($content);
 return $content;
}