使用PHP DOMDocument时nextSibling不起作用 [英] nextSibling doesn't work when working with PHP DOMDocument
问题描述
我尝试使用 nextSibling 获取以下元素，但以下代码无效。
我在
PHP下遇到错误，警告：第35行的/php/dom.php中为foreach（）提供了无效的参数
I tried to get a following element using nextSibling and the following code doesn't work.
i've got an error as below
PHP Warning: Invalid argument supplied for foreach() in /php/dom.php on line 35
必须由foreach循环中的空值引起。
that must be caused by the null value in the foreach loop.
但是如果我使用 previousSibling 可以正常工作。
but if I modify it to get the previous element using previousSibling it works as expected.
$doc = new DOMDocument();
$html = <<<HTML
<html>
<body>
<ul id="list">
<li>Foo</li>
<li>Bar</li>
</ul>
<h2 class = 'test'>heading2</h2>
<ul id="list2">
<li>list1</li>
<li>list2</li>
</ul>
</body>
</html>
HTML;
$doc ->loadHTML($html);
$DOMNodelist = $doc->getElementsByTagName('*');
foreach($DOMNodelist as $node) {
if ($node -> hasAttribute('class')) {
foreach($node -> nextSibling ->childNodes as $morenodes) {
print_r($morenodes);
}
}
}
推荐答案
因为文档中的元素之间有空格，所以您实际上需要使用：
nextSibling-> nextSibling
或者，我会这样做，因为您已经有了一个'*'生成的所有元素的列表，我将其写为：
Because your document has whitespace separating the elements, you'd actually need to use:
nextSibling->nextSibling
Or, the way I'd do it, because you already have a list generated from '*' for all the elements, I'd write it as:
foreach($DOMNodelist as $i=>$node) {
if ($node -> hasAttribute('class')) {
foreach($DOMNodelist->item($i+1)->childNodes as $morenodes) {
print_r($morenodes);
}
}
}
或者您也可以删除文档中的空白：
Or you can just remove the whitespace from the document:
$html = <<<HTML
<html><body><ul id="list"><li>Foo</li><li>Bar</li></ul><h2 class = 'test'>heading3</h2><h3>heading3</h3><ul id="list2"><li>list2</li><li>list2</li></ul></body></html>
HTML;
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