if ($result){
echo '添加成功';
// header('refresh:3,url=user_nameList.php');
echo "<script> alert('添加成功');location.href='user_nameList.php'</script>";
}else{
echo '添加失败';
// header('refresh:3,url=userName_insert.php');
echo "<script>alert('添加失败');location.href='userName_insert.php'</script>";
}

js  location.href 和 php  header 跳转方式_php