Generate member account in php_PHP tutorial

function get_number($table,$filed){
	if(!isset($table) || !isset($filed)){
		return '';
	}
	if(trim($table)=='' || trim($filed)==''){
		return '';
	}
	global $db;
	$user_number=str_shuffle(substr(randomname(-5),11));
	$sql="select `id` from `".$table."` where `".$filed."`='".$user_number."'";
	if($db->getRowsNum($sql) || strpos($user_number,'0')==0){
		get_number($table,$filed);
	}
	return $user_number;
}

/***********生成随机数[随机数是后五位，一共是19位]****************/
function randomname($start,$len=''){
	if(!isset($start) || !is_numeric($start) || ($len!='' && !is_numeric($len))){
		return '';
	}echo '-----';
	$seedstr=explode(' ',microtime(),5); 
	$seed=$seedstr[0]*10000; 
	$random=date('YmdHis', time()).rand(10000,100000);
	return $len===''?substr($random,$start):substr($random,$start,$len);
}