使用 DOM 循环遍历“body”标签的所有元素答案

【问题标题】：Loop through all elements of "body" tags using DOM使用 DOM 循环遍历“body”标签的所有元素
【发布时间】：2011-05-24 18:53:52
【问题描述】：

$html = file_get_contents("test.html");
$doc = new DOMDocument();
$doc->loadHTML($html);
$xpath = new DOMXPath($doc);
$body = $xpath->query('//body');

我想遍历 HTML 文件的 body 标记的所有元素并打印出与这些元素关联的“样式”属性。我该怎么做？

【问题讨论】：

是body元素的直接子元素还是body下面的整个元素树？
我的意思是 body 下面的整个元素树 :)

标签： php html loops dom

【解决方案1】：

另一种选择是使用 XPath 仅查找源自 <body> 并具有 style 属性的元素，例如：

$dom = new DOMDocument;
$dom->loadHTMLFile('https://stackoverflow.com/questions/4431142/');

$xpath = new DOMXPath($dom);
$nodes = $xpath->query('/html/body//*[@style]');

foreach($nodes as $node) {
    printf(
        'Element %s - Styles: %s%s',
        $node->nodeName,
        $node->getAttribute('style'),
        PHP_EOL
    );
}

输出与Gordon's answer 中的相同，唯一重要的行是$nodes = … 一行。

【讨论】：

【解决方案2】：

您可以为此使用我的RecursiveDOMIterator：

代码（压缩）

class RecursiveDOMIterator implements RecursiveIterator
{
    protected $_position;
    protected $_nodeList;
    public function __construct(DOMNode $domNode)
    {
        $this->_position = 0;
        $this->_nodeList = $domNode->childNodes;
    }
    public function getChildren() { return new self($this->current()); }
    public function key()         { return $this->_position; }
    public function next()        { $this->_position++; }
    public function rewind()      { $this->_position = 0; }
    public function valid()
    {
        return $this->_position < $this->_nodeList->length;
    }
    public function hasChildren()
    {
        return $this->current()->hasChildNodes();
    }
    public function current()
    {
        return $this->_nodeList->item($this->_position);
    }
}

用法：

$dom = new DOMDocument;
$dom->loadHTMLFile('http://stackoverflow.com/questions/4431142/');

$dit = new RecursiveIteratorIterator(
    new RecursiveDOMIterator($dom),
    RecursiveIteratorIterator::SELF_FIRST
);

foreach($dit as $node) {
    if($node->nodeType === XML_ELEMENT_NODE && $node->hasAttribute('style')) {
        printf(
            'Element %s - Styles: %s%s',
            $node->nodeName,
            $node->getAttribute('style'),
            PHP_EOL
        );
    }
}

输出：

Element div - Styles: margin-top: 8px; height:24px;
Element div - Styles: margin-top: 8px; height:24px; display:none;
Element a - Styles: font-size: 200%; margin-left: 30px;
Element div - Styles: display:none
Element div - Styles: display:none
Element span - Styles: color:#FE7A15;font-size:140%
Element span - Styles: color:#FE7A15;font-size:140%
Element span - Styles: color:#FE7A15;font-size:140%
Element span - Styles: color:#E8272C;font-size:140%
Element span - Styles: color:#00AFEF;font-size:140%
Element span - Styles: color:#969696;font-size:140%
Element span - Styles: color:#46937D;font-size:140%
Element span - Styles: color:#C0D0DC;font-size:140%
Element span - Styles: color:#000;font-size:140%
Element span - Styles: color:#dd4814;font-size:140%
Element span - Styles: color:#9ce4fe;font-size:140%
Element span - Styles: color:#cf4d3f;font-size:140%
Element span - Styles: color:#f4f28d;font-size:140%
Element span - Styles: color:#0f3559;font-size:140%
Element span - Styles: color:#f2f2f2;font-size:140%
Element span - Styles: color:#037187;font-size:140%
Element span - Styles: color:#f1e7cc;font-size:140%
Element span - Styles: color:#e1cdae;font-size:140%
Element span - Styles: color:#a2d9f6;font-size:140%

【讨论】：

非常感谢您的回答。它很棒而且很棒，完全按照我的预期工作:)

【解决方案3】：

我是这样递归地做的。我不确定它是否是最有效的方法。我在这个网页上试过这个方法，效果很好。

$dom = new DOMDocument();
$dom->loadHTML($html);

$xpath = new DOMXPath($dom);
$body = $xpath->query('//body')->item(0);

recursePrintStyles($body);

function recursePrintStyles($node)
{
    if ($node->nodeType !== XML_ELEMENT_NODE)
    {
        return;
    }

    echo $node->tagName;
    echo "\t";
    echo $node->getAttribute('style');
    echo "\n";

    foreach ($node->childNodes as $childNode)
    {
        recursePrintStyles($childNode);
    }
}

【讨论】：