Minimized script elements are interpreted as open elements by Internet Explorer up to version 6.x. It follows that
<script type="text/javascript" src="..." />
will be seen as
<script type="text/javascript" src="...">
This will effectively consume any elements following. So when a script element appears within the head element, an entire document can disappear! This, of course, is the workaround:
<script type="text/javascript" src="..."></script>