如何使用PHP替换字符串中的开始和结束h1标签？

I have captured the <h1> tag and its inner contents from a webpage and I need to remove the <h1> and </h1> parts of the string. The problem is that I won't know if the tag is written as <h1> or <h1 id="something">, etc. I know I can write

$tag = str_replace("<h1>", '', $tag);
$tag = str_replace("</h1>", '', $tag); 

But how can I handle the more general case, where it may be <h1 id="something">, or something else?

Look at strip_tags http://php.net/manual/en/function.strip-tags.php