xml generated not opening in browser - php

Question

I wrote php code to create an xml but the xml file is not opening in browser
The following is the code:
$dom = new DOMDocument('1.0','UTF-8');
$dom->formatOutput = true;
$root = $dom->createElement('journal');
$dom->appendChild($root);
$journal_metadata = $dom->createElement('journal_metadata');
$dom->appendChild($journal_metadata);
$journal_metadata->appendChild($dom->createElement('full_title', 'Economics'));
$journal_metadata->appendChild($dom->createElement('abbrev_title', 'JJD'));
$issn = $dom->createElement('issn','2142');
$journal_metadata->appendChild($issn);
$issn->setAttribute('media_type', 'electronic');
$journal_metadata->appendChild($dom->createElement('doi_data', 'JJD'));
$doi_data = $dom->createElement('doi_data');
$journal_metadata->appendChild($doi_data);
$doi = $dom->createElement('doi', '10.E');
$doi_data->appendChild($doi);
$resource = $dom->createElement('resource', 'http://localhost/fo/journal.php?jid=1');
$doi_data->appendChild($resource);
// journal issue
$journal_issue = $dom->createElement('journal_issue');
$dom->appendChild($journal_issue);
// journal article
$journal_article = $dom->createElement('journal_article');
$dom->appendChild($journal_article);
$journal_article->setAttribute('publication_type', 'full_text');
$pages = $dom->createElement('pages');
$journal_article->appendChild($pages);
$resource = $dom->createElement('resource', htmlspecialchars('http://localhost/fo/abstracts.php?artID=472&jid=1'));
$doi_data->appendChild($resource);
echo '<xmp>'. $dom->saveXML() .'</xmp>';
$dom->save('result.xml') or die('XML Create Error');