PHP XPath查询什么都不返回

Question

I've been recently playing with DOMXpath in PHP and had success with it, trying to get more experience with it I've been playing grabbing certain elements of different sites. I am having trouble getting the weather marker off of http://www.theweathernetwork.com/weather/cape0005 this website.

Specifically I want

//*[@id='theTemperature']

Here is what I have

$url = file_get_contents('http://www.theweathernetwork.com/weather/cape0005');

$dom   = new DOMDocument();
@$dom->loadHTML($url);
$xpath = new DOMXPath($dom);
$tags  = $xpath->query("//*[@id='theTemperature']");
foreach ($tags as $tag){
    echo $tag->nodeValue;
}

Is there something I am doing wrong here? I am able to produce actual results on other tags on the page but specifically not this one.

Thanks in advance.

Answer 1

what happens is straightforward, the page contains an empty id="theTemperature" element which is a placeholder to be populated with javascript. file_get_contents() will just download the page, not executing javascript, so the element remains empty. Try to load the page in the browser with javascript disabled to see it yourself