Question

why does this

$html = '<a href="/browse/product.do?cid=1&amp;vid=1&amp;pid=1" class="productItemName">what is going on here</a>';

$dom = new DOMDocument();
$dom->loadhtml($html);
$xpath = new DOMXPath($dom);

$selectors['link'] = '//a/@href';
$links_nodeList = $xpath->query($selectors['link']);

foreach ($links_nodeList as $link) {
    $links[] = $link->nodeValue;
}

echo("<p>links</p>");
echo("<pre>");
print_r($links);
echo("</pre>");

output

links

Array
(
    [0] => /browse/product.do?cid=1&vid=1&pid=1
)

and not

links

Array
(
    [0] => /browse/product.do?cid=1&vid=1&pid=1
)

?

Answer 1

The answer is simple:

& is a special way to represent the character "&" in an XML document.

These two denote the same character.

When the escaped form of the ampersand is output as text (not as XML), showing it as "&" is correct.

As further elaborated by @LarsH in his comment:

when you say loadhtml($html);, you are parsing the string as HTML,
which means that character entities (like &) are interpreted
into the characters they represent (like &). If you want a string
that will be interpreted as &, you need to escape the ampersand,
e.g. &