如何使用PHP通过类名或ID获取innerhtml [英] how to get innerhtml by classname or id using php
问题描述
我正在从外部URL加载内容.像这样的东西.
Hi i am loading content from external url. something like this.
$html=get_data($external_url);
其中get_data()是用于使用curl获取内容的函数.
where get_data() is a function for getting content using curl.
现在，我想通过使用它们的类或id从不同的html元素(如h1，div，p，span)中获取内部html.
now after this , i want to get the inner html from different html elements like h1,div,p,span by using their class or id.
例如 如果来自外部url($ html)的内容是这样的.
for example if the content from external url($html) is something like this.
<html>
<title></title>
<body>
<h1 class="title">I am title</h1>
<div id="content">
i am the content.
</div>
</body>
现在我想获取class ="title"的html标签的内部html.类似地，我想获取带有id ="content"
now i want to get the inner html of a html tag with class="title". similarly i want to get inner html of a tag with id="content"
如何使用php做到这一点?我不了解DOM，XML.请帮忙.
How to do this using php? i have no knowledge about DOM, XML. please help.
推荐答案
这是函数DOMDocument::saveHTML().在当前的php版本中，这可能需要将您要另存为html的节点.要保存节点的内部html，必须保存每个子节点.
Here is a function DOMDocument::saveHTML(). In the current php versions, this can take a node you want to save as html. To save the inner html of a node, you have to save each child node.
function getHtml($nodes) {
$result = '';
foreach ($nodes as $node) {
$result .= $node->ownerDocument->saveHtml($node);
}
return $result;
}
要获取节点，可以使用Xpath. id很简单.
To fetch the nodes, you can use Xpath. The id is easy.
获取所有元素节点:
//*
具有id属性"content"的
that have the id attribute "content"
//*[@id="content"]
仅使用第一个找到的节点，以防有人多次添加相同的ID.
Use only the first found node, in case somebody added the same id multiple times.
//*[@id="content"][1]
获取子节点-node()包含元素，文本和其他几个节点
Get the child nodes - node() includes element, text and several other nodes
//*[@id="content"][1]/node()
$dom = new DOMDocument();
$dom->loadHTML($html);
$xpath = new DOMXpath($dom);
echo getHtml($xpath->evaluate('//*[@id="content"][1]/node()'));
class属性稍微复杂一些.类属性是令牌列表，它们可以包含多个类名称.这是匹配它们的一个技巧. Xpath函数normalize-space()将所有空白空间组转换为单个空格分隔符.在开头和结尾处添加一个空格，您将得到一个类似于" one two three "的字符串.现在，您可以检查" one "是否是该字符串的一部分.在Xpath中:
The class attribute is a little more complex. Class attributes are token lists, they can contain several class names. Here is a trick to matching them. The Xpath function normalize-space() converts all groups of whitespaces into single space separators. Add a space in front and to the end and you get a string like " one two three ". Now you can check if " one " is a part of that string. In Xpath:
标准化class属性:
Normalize the class attribute:
normalize-space(@class)
添加空格以开始和结束:
Add spaces to start and end:
concat(" ", normalize-space(@class), " ")
检查它是否包含子字符串
Check if it contains the substring
contains(concat(" ", normalize-space(@class), " "), " title ")
使用它来限制节点
//*[contains(concat(" ", normalize-space(@class), " "), " title ")][1]/node()
放在一起:
$html = <<<'HTML'
<html>
<title></title>
<body>
<h1 class="title">I am title</h1>
<div id="content">
i am the <b>content</b>.
</div>
</body>
HTML;
$dom = new DOMDocument();
$dom->loadHTML($html);
$xpath = new DOMXpath($dom);
function getHtml($nodes) {
$result = '';
foreach ($nodes as $node) {
$result .= $node->ownerDocument->saveHtml($node);
}
return $result;
}
// first node with the id
var_dump(
getHtml(
$xpath->evaluate('//*[@id="content"][1]/node()')
)
);
// first node with the class
var_dump(
getHtml(
$xpath->evaluate(
'//*[contains(concat(" ", normalize-space(@class), " "), " title ")][1]/node()'
)
)
);
// alternative - handling multiple nodes with the same class in a loop
$nodes = $xpath->evaluate(
'//*[contains(concat(" ", normalize-space(@class), " "), " title ")]'
);
foreach ($nodes as $node) {
var_dump(getHtml($xpath->evaluate('node()', $node)));
}
string(40) "
i am the <b>content</b>.
"
string(10) "I am title"
string(10) "I am title"
这篇关于如何使用PHP通过类名或ID获取innerhtml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！
