使用PHP Simple HTML DOM Parser从html中提取dom元素

I'm trying to extract links to the articles including the text, from this site using PHP Simple HTML DOM PARSER.

I want to extract all h2 tags for articles in the main page and I'm trying to do it this way:

    $html = file_get_html('http://www.winbeta.org');
    $articles = $html->getElementsByTagName('article');
    $a = null;

    foreach ($articles->find('h2') as $header) {
                $a[] = $header;
    }

    print_r($a);

according to the manual it should first get all the content inside article tags then for each article extract the h2 and save in array. but instead it gives me :

EDIT

There are several problems:

• getElementsByTagName apparently returns a single node, not an array, so it would not work if you have more than one article tag on the page. Instead use find which does return an array;
• But once you make that switch, you cannot use find on a result of find, so you should do that on each individual matched article tag, or better use a combined selector as argument to find;
• Main issue: You must retrieve the text content of the node explicitly with ->plaintext, otherwise you get the object representation of the node, with all its attributes and internals;
• Some of the text contains HTML entities like ’. These can be decoded with html_entity_decode.

So this code should work:

$a = array();
foreach ($html->find('article h2') as $h2) { // any h2 within article
    $a[] = html_entity_decode($h2->plaintext);
}

Using array_map, you could also do it like this:

$a = array_map(function ($h2) { return html_entity_decode($h2->plaintext); }, 
               $html->find('article h2'));

If you need to retrieve other tags within articles as well, to store their texts in different arrays, then you could do as follows:

$a = array();
$b = array();
foreach ($html->find('article') as $article) {
    foreach ($article->find('h2') as $h2) {
        $a[] = html_entity_decode($h2->plaintext);
    }
    foreach ($article->find('h3') as $h3) {
        $b[] = html_entity_decode($h3->plaintext);
    }
}