How do I avoid a page break immediately after a heading

Question

I have an HTML 4.01/CSS 2.1 document that includes an H3 heading followed by a short (one line) paragraph block and then an unordered list with several items:

<h3>Heading!</h3>

<p>Some things:</p>

<ul>
  <li>Thing one</li>
  <li>Thing B</li>
  <li>Thing 4</li>
</ul>

My problem is that when I print the document (or render it as a PDF using wkhtmltopdf), sometimes a page break will occur right after the heading, before the paragraph, which looks quite silly.

Is there a way to stipulate that page breaks should be avoided immediately after a header? (I'm not averse to HTML5/CSS3 solutions, if that simplifies things significantly.)

Note: following suggestions, I tried using the CSS property page-break-after: avoid. This doesn't really work in any WebKit or Mozilla based browsers, though.

Answer 1

This is an extremely hacky solution, but it works for me:

h1 {
    page-break-inside: avoid;
}
h1::after {
    content: "";
    display: block;
    height: 100px;
    margin-bottom: -100px;
}

Basically I create an invisible element that increases the size of the <h1> without affecting the content after it. When page-break-inside: avoid is applied and the whole <h1> (including the hacky element cannot fit into the page) the browser is forced to carry the <h1> to the next page.