我想替换标题中的关键字，如"the"、"and"等，并在标题标记中用span替换。
例如：
<h2>This is the heading</h2>
成为
<h2>This is <span>the</span> heading</h2>
感谢的帮助
更新
我找到了一个能满足我需求的东西：
$(function() {
$('h2').each(function(i, elem) {
$(elem).html(function(i, html) {
return html.replace(/the/, "<span>the</span>");
});
});
});
仅限PHP的解决方案（不含正则表达式）：
$string = "<h2>This is the heading</h2>";
$toReplace = array("the", "and");
$replaceTo = array_map(function ($val) { return "<span>$val</span>"; }, $toReplace);
$newString = str_replace($toReplace, $replaceTo, $string);
print $newString; // prints as expected: <h2>This is <span>the</span> heading</h2>
这段代码将帮助您做到这一点，并动态扩展您的单词：
$special_words = array("the", "and", "or") ;
$words = implode("|", $special_words) ;
$string = "<h2>This is the heading</h2>" ;
$new = preg_replace("/({$words})/i", "<span>$1</span>", $string) ;
echo $new ;
使用regexp非常简单，这个例子只使用一个关键字，对于多个关键字使用一个数组。
$string = "<h2>This is the heading</h2>";
$string = preg_replace("/(the|end)/", "<span>$1</span>", $string);