Page-break-after: avoid working only in IE?

I cannot get this CSS to work in Chrome and Firefox.

p { page-break-inside: avoid; }
h1 { page-break-after: avoid; }

Html:

<h1>FOO</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
<h1>FOO</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
[..]

Chrome and Firefox insert a page break after an element <h1>when printing.

Only IE saves h1 + p together.

HTML is generated ( https://github.com/chjj/marked ), so I would prefer to solve this with CSS, if possible.

• JSFiddle: http://jsfiddle.net/QCvA5/86/
• Exit: http://jsfiddle.net/QCvA5/86/show/