A tip I picked up from various sites, including This One

Very useful for preventing printing of Perception quizzes, when you cannot use Questionmark's secure browser.

Stick this in the template for the quiz:

HTML_HEADER=

<!--open HTML_HEADER-->

<STYLE media="print">BODY {display:none}</STYLE>




<!--close HTML_HEADER-->

for non-questionmark-related printing prevention, just stick

<STYLE media="print">BODY {display:none}</STYLE>

in the head of the document.

Seems to work in Netscape for PC also, but I haven't yet tried it on the mac.