/**
 * 获取分类下的所有子类
 * @param unknown $arrCat
 * @param number $parent_id
 * @param number $level
 * @param string $all
 * @return boolean|Ambigous <unknown, string, number>
 */
function get_category_child($arrCat, $parent_id = 0, $level = 0,$all=true){
	global $arrTree;
	if(!$all) $arrTree ='';
	if(empty($arrCat)) return false;
	$level++;
	if($level == 1) $arrTree[] = $parent_id;
	foreach($arrCat as $key => $value){
		if($value['pid' ] == $parent_id){
			//$value[ 'level'] = $level;
			$arrTree[] = $value['id'];
			unset($arrCat[$key]); //注销当前节点数据,减少已无用的遍历
			get_category_child($arrCat, $value['id'], $level);
		}
	}
	return $arrTree;
}
/**
 * 替换文章内容的图片
 */
function replace_img($content){
	$domain = 'http://'.$_SERVER['SERVER_NAME'];
	preg_match_all("/<(.*)(src=\"[^\"]+\")[^>]+>/isU", $content, $match);
	foreach($match[2] as $img){
		$content = str_replace($img, 'src="'.$domain.substr($img,5),$content);
	}
	return $content;
}