<?php
require_once('simple_html_dom.php');

$html = file_get_html('https://mkb10.su/F10-F19.html');
$data =[];
$i = 0;
foreach($html->find('ol.tm-list-additional-space li') as $element) {
    $data[$i] = [
        'code' => $element->find('span', 0)->plaintext,
        'name' => $element->find('a', 0)->plaintext,
    ];

    $htmlT = file_get_html('https://mkb10.su/'.$element->find('a', 0)->href);
    foreach($htmlT->find('ol.tm-list-additional-space li') as $e) {
        $data[$i]['sub'][] = [
            'code' => $e->find('span', 0)->plaintext,
            'name' => $e->find('a', 0)->plaintext,
        ];

    }
    $i++;
}
echo json_encode($data);