如果它包含 html（请注意，这是一个非常强大的解决方案）：
$string = '<p>foo<b>bar</b></p>';
$keyword = 'foo';
$dom = new DomDocument();
$dom->loadHtml($string);
$xpath = new DomXpath($dom);
$elements = $xpath->query('//*[contains(.,"'.$keyword.'")]');
foreach ($elements as $element) {
foreach ($element->childNodes as $child) {
if (!$child instanceof DomText) continue;
$fragment = $dom->createDocumentFragment();
$text = $child->textContent;
$stubs = array();
while (($pos = stripos($text, $keyword)) !== false) {
$fragment->appendChild(new DomText(substr($text, 0, $pos)));
$word = substr($text, $pos, strlen($keyword));
$highlight = $dom->createElement('span');
$highlight->appendChild(new DomText($word));
$highlight->setAttribute('class', 'highlight');
$fragment->appendChild($highlight);
$text = substr($text, $pos + strlen($keyword));
}
if (!empty($text)) $fragment->appendChild(new DomText($text));
$element->replaceChild($fragment, $child);
}
}
$string = $dom->saveXml($dom->getElementsByTagName('body')->item(0)->firstChild);
结果是：
<p><span class="highlight">foo</span><b>bar</b></p>
与：
$string = '<body><p>foobarbaz<b>bar</b></p></body>';
$keyword = 'bar';
你得到（为了可读性分成多行）：
<p>foo
<span class="highlight">bar</span>
baz
<b>
<span class="highlight">bar</span>
</b>
</p>
谨防非 dom 解决方案（例如regex or str_replace）因为突出显示诸如“div”之类的内容有可能完全破坏您的 HTML...这只会“突出显示”正文中的字符串，而永远不会“突出显示”标签内的字符串...
Edit既然你想要 Google 风格的结果，这里有一种方法：
function getKeywordStubs($string, array $keywords, $maxStubSize = 10) {
$dom = new DomDocument();
$dom->loadHtml($string);
$xpath = new DomXpath($dom);
$results = array();
$maxStubHalf = ceil($maxStubSize / 2);
foreach ($keywords as $keyword) {
$elements = $xpath->query('//*[contains(.,"'.$keyword.'")]');
$replace = '<span class="highlight">'.$keyword.'</span>';
foreach ($elements as $element) {
$stub = $element->textContent;
$regex = '#^.*?((\w*\W*){'.
$maxStubHalf.'})('.
preg_quote($keyword, '#').
')((\w*\W*){'.
$maxStubHalf.'}).*?$#ims';
preg_match($regex, $stub, $match);
var_dump($regex, $match);
$stub = preg_replace($regex, '\\1\\3\\4', $stub);
$stub = str_ireplace($keyword, $replace, $stub);
$results[] = $stub;
}
}
$results = array_unique($results);
return $results;
}
好的，那么它的作用是返回一个匹配数组$maxStubSize周围的单词（即之前的数字最多一半，之后的数字最多一半）...
所以，给定一个字符串：
<p>a whole
<b>bunch of</b> text
<a>here for</a>
us to foo bar baz replace out from this string
<b>bar</b>
</p>
Calling getKeywordStubs($string, array('bar', 'bunch'))将导致：
array(4) {
[0]=>
string(75) "here for us to foo <span class="highlight">bar</span> baz replace out from "
[3]=>
string(34) "<span class="highlight">bar</span>"
[4]=>
string(62) "a whole <span class="highlight">bunch</span> of text here for "
[7]=>
string(39) "<span class="highlight">bunch</span> of"
}
因此，您可以通过对列表进行排序来构建结果简介strlen然后选择两个最长的匹配...（假设 php 5.3+）：
usort($results, function($str1, $str2) {
return strlen($str2) - strlen($str1);
});
$description = implode('...', array_slice($results, 0, 2));
结果是：
here for us to foo <span class="highlight">bar</span> baz replace out...a whole <span class="highlight">bunch</span> of text here for
我希望这有帮助...（我确实觉得这有点...臃肿...我确信有更好的方法可以做到这一点，但这是一种方法）...
