NOSCRIPT works like a standard tag, with a start and an end. You can place whatever you want between start and end tag. For the most part, writing only a short text is the smartest thing to do, possibly with a picture, in a typography which is easy to spot. It might be something like:
<NOSCRIPT STYLE="font-size:16.0pt; color:red; font-weight:bold"><IMG SRC="Graphics/ComputerWork.gif" STYLE="float:right">This page requires JavaScript to be enabled to work properly.</NOSCRIPT>
If JavaScript is disabled, the result looks like this:
This page requires JavaScript to be enabled to work properly.
If JavaScript is enabled, the content is left out, so it is not going to give you a blank area on the page (i.e. a white-out) where the content of the NOSCRIPT was supposed to be.