class HtmlFilter
{
    /**
     * 过滤字符串中的特殊字符
     * @static
     * @param $content
     * @return string
     */
    public static function filterSpacialHtmlChar($content)
    {
 
        if (empty($content)) {
            return '';
        }
        $content=self::delAllSpace($content);
        $content=self::replaceHtmlAndJs($content);
 
        return strip_tags($content);
    }
 
    /**
     * 生成摘要
     * @static
     * @param $content
     * @param $len
     * @param string $char
     * @return string
     */
    public static  function getSummary($content,$len=100,$char='UTF-8'){
        if(empty($content)){
            return '';
        }
 
        if($len>=mb_strlen($content)){
          return self::filterSpacialHtmlChar($content);
        } // www.
 
        return mb_substr(self::filterSpacialHtmlChar($content),0,$len,$char).'...';
    }
 
    /**
     * 去掉 $str中的特殊字符
     * @static
     * @param $document
     * @return mixed|string
     */
    public static function replaceHtmlAndJs($document)
    {
        $document = trim($document);
        if (strlen($document)