自动生成sitemap地图PHP代码

<?php
$dom = new DOMDocument("1.0", "utf-8");
header("Content-Type: text/xml");
$root = $dom->createElement("urlset");
$dom->appendChild($root);
for ($i = 0; $i <= 998; $i++) {
    $track = $dom->createElement("url");
    $root->appendChild($track);
    $loc = $dom->createElement("loc");
    $track->appendChild($loc);
    $lastmod = $dom->createElement("lastmod");
    $track->appendChild($lastmod);
    $changefreq = $dom->createElement("changefreq");
    $track->appendChild($changefreq);
    $priority = $dom->createElement("priority");
    $track->appendChild($priority);
    $text = $dom->createTextNode('http://www.baidu.com/' . (mt_rand(1,20)) . ($i+1) . '.html');
    $loc->appendChild($text);
    $date = date("Y-m-d", strtotime('-' . rand(0,10) . 'day'));
    $text = $dom->createTextNode($date);
    $lastmod->appendChild($text);
    $text = $dom->createTextNode(daily);
    $changefreq->appendChild($text);
    $text = $dom->createTextNode(0.8);
    $priority->appendChild($text);
}
$dom->save("sitemap.xml");
exit;