求解此段php代码语法有何错误

 <?php
if($type == "sub"){
    $username = $_POST['username'];
    $old_pass = $_POST['old_password'];
    $new_pass = $_POST['new_password'];
    $re_pass = $_POST['re_password'];
//表单验证
    if(!preg_match('/^[0-9[a-z]*$/',$username)){
        echo "<script>alert('用户名不合法')</script>";
        echo "<script>location.href='account_manage.php'</script>";
        exit;
    }else{
    if($username=='' or $old_pass=='' or $new_pass=='' or $re_pass==''){
        echo "<script>alert('请输入必填项')</script>";
        echo "<script>location.href='account_manage.php'</script>";
        exit;
    }else{
    if(!preg_match('/^[0-9[a-z]*$/',$new_pass)){
        echo "<script>alert('新密码不能含有特殊字符')</script>";
        echo "<script>location.href='account_manage.php'</script>";
        exit;
    }else{
    if($new_pass<>$re_pass){
        echo "<script>alert('确认密码输入错误')</script>";
        echo "<script>location.href='account_manage.php'</script>";
        exit;
    }
}
?>

运行后错误如下：
Parse error: syntax error, unexpected end of file in

大括号没有配对，你核对一下。

代码最后少了一个大括号，没个好的编辑器吗，有些代码没缩进，看的别扭