而是使用 preg_replace 为此:

preg_replace("/[\s]*
/", $title, $content);

不管你怎么做，它都没有真正的意义.<h2> 已启动，但是您删除了该结束标记和 <ol> 的开始标记，我假设它们也将具有结束标记?无论如何，您的输出似乎都会出错.

On a html page I have this.

</h2>
<ol>

The page is contained in a variable called $content. I want to replace this with something else but the code doesn't work.

$content = str_replace("</h2><ol>", $title, $content);

What should i put there instead of .

Rather use preg_replace for this:

preg_replace("/<\/h2>[\s]*<ol>/", $title, $content);

Regardless of how you do it, it doesn't really make sense. An <h2> is started, but you remove that closing tag and the starting tag for the <ol>, which will also have a closing tag I assume? Seems like your output is going to be wrong regardless.