php dom文件loadHTML和getElementByTagName什么都不返回(php dom document loadHTML and getElementByTagName return

php dom文件loadHTML和getElementByTagName什么都不返回(php dom document loadHTML and getElementByTagName returns nothing) $urlToScrap = "https://play.google.com/store/apps/details?id=flipboard.app#?t=W251bGwsMSwxLDIxMiwiZmxpcGJvYXJkLmFwcCJd"; $pageContentData = file_get_contents($urlToScrap); $doc = new DOMDocument(); $doc->loadHTML($pageContentData); $listOfDivs = $doc->getElementsByTagName("div"); foreach ($listOfDivs as $div) { if($div->getAttribute("class") == "doc-banner-icon"){ $img = $div->getElementsByTagName("img"); var_dump($img->getAttribute("src")); } }

返回空。

我在dom中有以下元素：

<div class="doc-banner-icon"><img src="somesrc"></div>

我正在尝试获取img src，因为在页面中有很多图像，我想首先获取父div，然后在其中提取图像。

解决方案在这里：

$urlToScrap = "https://play.google.com/store/apps/details?id=flipboard.app#?t=W251bGwsMSwxLDIxMiwiZmxpcGJvYXJkLmFwcCJd"; $pageContentData = file_get_contents($urlToScrap); $doc = new DOMDocument(); $doc->loadHTML($pageContentData); $listOfDivs = $doc->getElementsByTagName("div"); foreach ($listOfDivs as $div) { if($div->getAttribute("class") == "doc-banner-icon"){ $listOfImages = $div->getElementsByTagName("img"); foreach($listOfImages as $img){ var_dump($img->getAttribute("src")); } } } $urlToScrap = "https://play.google.com/store/apps/details?id=flipboard.app#?t=W251bGwsMSwxLDIxMiwiZmxpcGJvYXJkLmFwcCJd"; $pageContentData = file_get_contents($urlToScrap); $doc = new DOMDocument(); $doc->loadHTML($pageContentData); $listOfDivs = $doc->getElementsByTagName("div"); foreach ($listOfDivs as $div) { if($div->getAttribute("class") == "doc-banner-icon"){ $img = $div->getElementsByTagName("img"); var_dump($img->getAttribute("src")); } }

returns empty.

I have the following elements in the dom:

<div class="doc-banner-icon"><img src="somesrc"></div>

I'm trying to get the img src and since in the page there are many images, I would like to first get the parent div and then extract the image inside it.

The solution is here:

$urlToScrap = "https://play.google.com/store/apps/details?id=flipboard.app#?t=W251bGwsMSwxLDIxMiwiZmxpcGJvYXJkLmFwcCJd"; $pageContentData = file_get_contents($urlToScrap); $doc = new DOMDocument(); $doc->loadHTML($pageContentData); $listOfDivs = $doc->getElementsByTagName("div"); foreach ($listOfDivs as $div) { if($div->getAttribute("class") == "doc-banner-icon"){ $listOfImages = $div->getElementsByTagName("img"); foreach($listOfImages as $img){ var_dump($img->getAttribute("src")); } } }

最满意答案

你没有遗漏任何东西， var_dump不能像你期望的那样在DOMNodeList 。 试试这个：

$listOfImages = $doc->getElementsByTagName("img"); foreach ($listOfImages as $img) { $imgClass = $img->getAttribute('class'); echo $imgClass; }

在您更新的问题中，只需更改：

$img->getAttribute("src")

至：

$img->item(0)->getAttribute("src")

鉴于您的选择标准相当复杂，您可以考虑使用XPath而不是手动导航：

$doc = new DOMDocument(); $doc->loadHTML($pageContentData); $xpath = new DOMXPath($doc); $img = $xpath->query("//div[@class = 'doc-banner-icon']/img"); var_dump($img->item(0)->getAttribute('src'));

You aren't missing anything, var_dump doesn't work as you expect on a DOMNodeList. Try this instead:

$listOfImages = $doc->getElementsByTagName("img"); foreach ($listOfImages as $img) { $imgClass = $img->getAttribute('class'); echo $imgClass; }

In your updated question, just change:

$img->getAttribute("src")

to:

$img->item(0)->getAttribute("src")

Given that your selection criteria is fairly complex, you might consider using XPath instead of navigating manually:

$doc = new DOMDocument(); $doc->loadHTML($pageContentData); $xpath = new DOMXPath($doc); $img = $xpath->query("//div[@class = 'doc-banner-icon']/img"); var_dump($img->item(0)->getAttribute('src'));