查看源代码后，我发现解决方法是使用

After looking at the source code, I found that the way to go about it is to use

$var = "some JS stuff";
$e = $htmlDOM->find("body", 0);
$e->outertext = $e->makeup() . $e->innertext . $var . '</body>';

也就是说，未记录的makeup()函数将构建标记和任何关联的文本/代码.

That is, the undocumented makeup() function will build the tag and any associated text/code.