php - PHP：如何检查一个
有一个子节点 with DOMDocument?</a></h1> <div class="ml12 aside-cta flex--item print:d-none sm:ml0 sm:mb12 sm:order-first sm:as-end"> <a href="https://stackoverflow.com/questions/ask" target="_blank" class="ws-nowrap s-btn s-btnprimary">问问题</a></div> </div> <div class="d-flex fw-wrap pb8 mb16 bb bc-black-075"> <div class="flex--item ws-nowrap mr16 mb8"> <span class="fc-light mr2"></span> </div> <div class="flex--item ws-nowrap mr16 mb8" title="2022-04-17 15:46:40Z"> <span class="fc-light mr2">问问题</span> <time itemprop="dateCreated" datetime="2013-09-26T07:29:26.010">2013-09-26T07:29:26.010</time> </div> <div class="flex--item ws-nowrap mb8" title="Viewed 6 times"> <span class="fc-light mr2"></span> 2274 次 </div> </div> <div id="mainbar" role="main" aria-label="question and answers"> <div class="question" data-questionid="4" data-position-on-page="0" data-score="763" id="question"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="4"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-peeufs8c"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button> <div id="--stacks-s-tooltip-peeufs8c" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This question shows research effort; it is useful and clear<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value=""> 1 </div> <button class="js-vote-down-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-04106eqn"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button><div id="--stacks-s-tooltip-04106eqn" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This question does not show any research effort; it is unclear or not useful<div class="s-popover--arrow"></div></div> <div id="--stacks-s-tooltip-tgvwendx" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">Bookmark this question.<div class="s-popover--arrow"></div></div> <a class="js-post-issue flex--item s-btn s-btnunset c-pointer py6 mx-auto" data-shortcut="T" data-ks-title="timeline" data-controller="s-tooltip" data-s-tooltip-placement="right" aria-label="Timeline" aria-describedby="--stacks-s-tooltip-abwmy15k"><svg aria-hidden="true" class="mln2 mr0 svg-icon iconHistory" width="19" height="18" viewBox="0 0 19 18"><path d="M3 9a8 8 0 1 1 3.73 6.77L8.2 14.3A6 6 0 1 0 5 9l3.01-.01-4 4-4-4h3L3 9Zm7-4h1.01L11 9.36l3.22 2.1-.6.93L10 10V5Z"></path></svg></a><div id="--stacks-s-tooltip-abwmy15k" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">Show activity on this post.<div class="s-popover--arrow"></div></div> </div> </div> <div class="postcell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>How can I check if a <code>p</code> has a child node of <code>iframe</code> with <code>DOMDocument</code>?</p>

<p>For instance,</p>

<pre><code><p><iframe ....></p>
</code></pre>

<p>I want to print this only,</p>

<pre><code><iframe ....>
</code></pre>

<p>While,</p>

<pre><code><p>bla bla bal</p>
</code></pre>

<p>then do nothing or just print whatever inside the p,</p>

<pre><code><p>bla bla bal</p>
</code></pre>

<p>Or, </p>

<pre><code><p>bla bla <b>bal</b></p>
</code></pre>

<p>then do nothing or just print whatever inside the p,</p>

<pre><code><p>bla bla <b>bal</b></p>
</code></pre>

<p>my php,</p>

<pre><code>$dom = new DOMDocument;
$dom->loadHTML($item_html);

if($dom->getElementsByTagName('p')->length > 1 )
{
 ...
}
else // if it is only a single paragraph... then do what I want above...
{

 foreach ($dom->getElementsByTagName('p') as $node)
 {
 if ($node->hasChildNodes()) 
 {
 foreach( $dom->getElementsByTagName('iframe') as $iframe ) 
 {
 ... something
 }
 }
 else
 {
 ... 
 }
 }
}
</code></pre>

<p>is it possible?</p>
 </div> <div class="mt24 mb12"> <div class="post-taglist d-flex gs4 gsy fd-column"> <div class="d-flex ps-relative fw-wrap"> <a href="/tags/php" class="post-tag js-gps-track" title="show questions tagged 'php'" rel="tag">php</a><a href="/tags/iframe" class="post-tag js-gps-track" title="show questions tagged 'iframe'" rel="tag">iframe</a><a href="/tags/domdocument" class="post-tag js-gps-track" title="show questions tagged 'domdocument'" rel="tag">domdocument</a> </div> </div> </div> </div> <span class="d-none" itemprop="commentCount">4</span> </div> </div> <div class="js-zone-container zone-container-responsive"> <div id="dfp-isb" class="everyonelovesstackoverflow everyonelovesinline-sidebar mx-auto" style="min-height: auto; height: auto; display: none;"></div> <div class="js-report-ad-button-container mx-auto" style="width: 300px"></div> </div> <div id="answers"> <a name="tab-top"></a> <div id="answers-header"> <div class="answers-subheader d-flex ai-center mb8"> <div class="flex--item fl1"> <h2 class="mb0" data-answercount=""> 2 回答 <span style="display:none;" itemprop="answerCount">2</span> </h2> </div> </div> </div> <a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="3"> 3 </div> <button class="js-vote-down-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>You're trying to find all iframe elements that are the only childnodes of the p elements.</p>

<p>If found you want to replace their parent p element with them.</p>

<pre><code>/** @var DOMElement $p */
foreach ($doc->getElementsByTagName('p') as $p) {
 if ($p->childNodes->length !== 1) {
 continue;
 }

 $child = $p->childNodes->item(0);

 if (! $child instanceof DOMElement) {
 continue;
 }

 if ($child->tagName !== 'iframe') {
 continue;
 }

 $p->parentNode->insertBefore($child, $p);
 $p->parentNode->removeChild($p);
}
</code></pre>

<p>This foreach loop just iterates over all p elements, ignores all that don't have a single child node that is not a DOMElement with the iframe tagname (note: always lowercase in the compare).</p>

<p>If one p element is found, then the inner iframe is moved before it and then the paragraph is removed.</p>

<p>Usage Example:</p>

<pre><code><?php
/**
 * @link http://stackoverflow.com/q/19021983/367456
 */

$html = '
<p><iframe src="...."></p>
<p>bla bla bal</p>
<p>bla bla <b>bal</b></p>
<p></p>
';

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

/** @var DOMElement[] $ps */
// $ps = $;

/** @var DOMElement $p */
foreach ($doc->getElementsByTagName('p') as $p) {
 if ($p->childNodes->length !== 1) {
 continue;
 }

 $child = $p->childNodes->item(0);

 if (!$child instanceof DOMElement) {
 continue;
 }

 if ($child->tagName !== 'iframe') {
 continue;
 }

 $p->parentNode->insertBefore($child, $p);
 $p->parentNode->removeChild($p);
}

// output
foreach ($doc->getElementsByTagName('body')->item(0)->childNodes as $child) {
 echo $doc->saveHTML($child);
}
</code></pre>

<p><a href="https://eval.in/51220" rel="nofollow">Demo</a> and Output:</p>

<pre><code><iframe src="...."></iframe>
<p>bla bla bal</p>
<p>bla bla <b>bal</b></p>
<p></p>
</code></pre>

<p>Hope this is helpful. </p>
 </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2013-09-27T17:24:57.090 回答</div> </div> </div> </div> </div><a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="1"> 1 </div> <button class="js-vote-down-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>So do this:</p>

<pre><code> $dom = new DOMDocument;
 $dom->loadHTML($item_html);

 if($dom->getElementsByTagName('p')->length > 1 )
 {
 ...
 }
 else // if it is only a single paragraph... then do what I want above...
 {

 foreach ($dom->getElementsByTagName('p') as $node)
 {
 if ($node->hasChildNodes()) 
 {
 if($dom->getElementsByTagName('iframe')->length > 0 )
 {
 foreach( $dom->getElementsByTagName('iframe') as $iframe ) 
 {
 ... something
 }
 }
 }
 else
 {
 ... 
 }
 }
 }
</code></pre>
 </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2013-09-26T07:47:02.447 回答</div> </div> </div> </div> </div></div> </div> <div id="sidebar" class="show-votes" role="complementary" aria-label="sidebar"> <div class="module sidebar-related"> <h4 id="h-related">Related</h4> <div class="related js-gps-related-questions" data-tracker="rq=1"> <div class="spacer"> <a href="/questions/10237415" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">1</div> </a> <a href="/questions/10237415" class="question-hyperlink">android - testdroid 记录器与 acra</a> </div><div class="spacer"> <a href="/questions/10237416" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">4</div> </a> <a href="/questions/10237416" class="question-hyperlink">java - web.xml 中的欢迎文件，spring 不起作用？</a> </div><div class="spacer"> <a href="/questions/10237419" title="Question score (upvotes - downvotes)"> <div class="answer-votes 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