采集页面时，获取网页中所有的链接，并循环输出：

<?php
$html = file_get_contents('https://www.baidu.com');
$dom = new DOMDocument();
@$dom->loadHTML($html);
$xpath = new DOMXPath($dom);
$hrefs = $xpath->evaluate("/html/body//a");
for ($i = 0; $i < $hrefs->length; $i++) {
       $href = $hrefs->item($i);
       $url = $href->getAttribute('href');
       echo $url.'<br />';
}
?>