php 用php修改html属性
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Modify html attribute with php
提问by Linda
I have a html string that contains exactly one a-element in it. Example:
我有一个 html 字符串，其中正好包含一个 a 元素。例子：
<a href="http://www.test.com" rel="nofollow external">test</a>
In php I have to test if relcontains externaland if yes, then modify hrefand save the string.
在 php 中，我必须测试rel 是否包含外部，如果是，则修改href并保存字符串。
I have looked for DOM nodes and objects. But they seem to be too much for only one A-element, as I have to iterate to get html nodes and I am not sure how to test if relexists and contains external.
我一直在寻找 DOM 节点和对象。但是对于只有一个 A 元素来说，它们似乎太多了，因为我必须迭代以获取 html 节点，而且我不确定如何测试rel 是否存在并包含external。
$html = new DOMDocument();
$html->loadHtml($txt);
$a = $html->getElementsByTagName('a');
$attr = $a->item(0)->attributes();
...
At this point I am going to get NodeMapList that seems to be overhead. Is there any simplier way for this or should I do it with DOM?
在这一点上，我将获得似乎是开销的 NodeMapList。有没有更简单的方法，或者我应该用DOM来做吗？
采纳答案by u?nb??s
Is there any simplier way for this or should I do it with DOM?
有没有更简单的方法，或者我应该用DOM来做吗？
Do it with DOM.
用 DOM 来做。
Here's an example:
下面是一个例子：
<?php
$html = '<a href="http://example.com" rel="nofollow external">test</a>';
$dom = new DOMDocument;
$dom->loadHTML($html);
$xpath = new DOMXPath($dom);
$nodes = $xpath->query("//a[contains(concat(' ', normalize-space(@rel), ' '), ' external ')]");
foreach($nodes as $node) {
$node->setAttribute('href', 'http://example.org');
}
echo $dom->saveHTML();
回答by Linda
I kept going to modify with DOM. This is what I get:
我一直在用 DOM 进行修改。这就是我得到的：
$html = new DOMDocument();
$html->loadHtml('<?xml encoding="utf-8" ?>' . $txt);
$nodes = $html->getElementsByTagName('a');
foreach ($nodes as $node) {
foreach ($node->attributes as $att) {
if ($att->name == 'rel') {
if (strpos($att->value, 'external')) {
$node->setAttribute('href','modified_url_goes_here');
}
}
}
}
$txt = $html->saveHTML();
I did not want to load any other library for just this one string.
我不想只为这个字符串加载任何其他库。
回答by HamZa
The best way is to use a HTML parser/DOM, but here's a regex solution:
最好的方法是使用 HTML 解析器/DOM，但这里有一个正则表达式解决方案：
$html = '<a href="http://www.test.com" rel="nofollow external">test</a><br>
<p> Some text</p>
<a href="http://test.com">test2</a><br>
<a rel="external">test3</a> <-- This won\'t work since there is no href in it.
';
$new = preg_replace_callback('/<a.+?rel\s*=\s*"([^"]*)"[^>]*>/i', function($m){
if(strpos($m[1], 'external') !== false){
$m[0] = preg_replace('/href\s*=\s*(("[^"]*")|(\'[^\']*\'))/i', 'href="http://example.com"', $m[0]);
}
return $m[0];
}, $html);
echo $new;
在线演示。
回答by anthonybell
You could use a regular expression like
if it matches /\s+rel\s*=\s*".*external.*"/then do a regExp replace like
/(<a.*href\s*=\s*")([^"]\)("[^>]*>)/\1[your new href here]\3/
您可以使用正则表达式，
if it matches /\s+rel\s*=\s*".*external.*"/然后进行 regExp 替换，例如
/(<a.*href\s*=\s*")([^"]\)("[^>]*>)/\1[your new href here]\3/
Though using a library that can do this kind of stuff for you is much easier (like jquery for javascript)
尽管使用可以为您完成此类工作的库要容易得多（例如 jquery for javascript）
