PHP DOMDocument甚至跳过元素 [英] PHP DOMDocument skips even elements

问题描述

您好，我正在使用此方法将所有iframe和img标签替换为span标签

Hello I'm using this method to replace all iframe and img tags with span tags

    $string = clean($string);
    $dom = new \DOMDocument;
    $dom->loadHTML(mb_convert_encoding($string, 'HTML-ENTITIES', 'UTF-8'), LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
    $iframes = $dom->getElementsByTagName('iframe');

    foreach($iframes as $iframe) {
        $src = $iframe->getAttribute('src');
        $span = $dom->createElement('span');
        $span->setAttribute('title', $src);
        $span->setAttribute('class', 'lazy-youtube');
        $iframe->parentNode->replaceChild($span, $iframe);
    }

    $images = $dom->getElementsByTagName('img');

    foreach($images as $image) {
        $src = $image->getAttribute('src');
        $span = $dom->createElement('span');
        $span->setAttribute('title', $src);
        $span->setAttribute('class', 'lazy-image');
        $image->parentNode->replaceChild($span, $image);
    }

    $html = $dom->saveHTML();

    return clean($html);

但问题在于它会跳过始终像这样的元素

but problem is that it skips elements it's always like this

// Iframe
<span>
<iframe>
<span>
<iframe>
<span>
<iframe>
<span>
<iframe>

// Img
<span>
<img>
<span>
<img>
<span>
<img>
<span>
<img>

iframe的HTML

Html for iframes

<div class="content">
<p>
   <iframe frameborder="0" height="315" src="https://www.youtube.com/embed/T6kG5vuPVSs?rel=0" width="560"></iframe>
<p>
</p>
   <iframe frameborder="0" height="315" src="https://www.youtube.com/embed/GjnadPBMJGs?rel=0" width="560"></iframe>
<p>
</p>
   <iframe frameborder="0" height="315" src="https://www.youtube.com/embed/KYm8SLLQ0kk?rel=0" width="560"></iframe>
<p>
</p>
   <iframe frameborder="0" height="315" src="https://www.youtube.com/embed/xUVz4nRmxn4?rel=0" width="560"></iframe>
<p>
</p>
   <iframe frameborder="0" height="315" src="https://www.youtube.com/embed/hmZ6ziQJByY?rel=0" width="560"></iframe>
</p>
</div>

所有相同类型的元素具有相同的属性，只有src不同。谁知道我该如何修复它才能替换所有元素？

All same type of elements have same attributes, only src is different. Anyone know how can I fix it to replace all elements?

推荐答案

说明：问题是可能会跳过所有其他元素，因为例如，一旦删除iframe，对象（元素列表）就会发生变化，所有其他iframe都会移动以占据被删除的位置。

Explanation of the problem: It's probably skipping every other element because once you remove an iframe, for example, the object (the list of elements) changes in a way that all other iframes shift to ocuppy the removed's spot.

一个修复的方式：

// code
$iframes = $dom->getElementsByTagName('iframe');
while($iframes->length > 0){ // while there are still frames left to change
    foreach($iframes as $iframe) {
        // your regular code to replace iframe with span
        // break; // this makes it easier to understand, but not really necessary
    }
    $iframes = $dom->getElementsByTagName('iframe'); // get the (remaining) skipped frames until there is none left
}
// code

别忘了对图像做同样的事情。

这是一个更好的方法了解问题所在：

Here is a better way to understand the problem:

 1 - List of iframes
 iframe1  iframe2  iframe3  iframe4 iframe5 [...]
    /\ - current item in loop

 2 - Replacing iframe1, it comes out of the list (since I just want iframes), so the list is now:
 iframe2  iframe3  iframe4  iframe5 [...]
    /\

 3 - Loop continues and it goes to the next item
 iframe2  iframe3  iframe4  iframe5 [...]
             /\ - current item in loop

看看那样，它将跳过其他所有元素吗？

See how, that way, it would skip every other element?

这篇关于PHP DOMDocument甚至跳过元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！