<hst:headcontribution> strips javascript code from <script>-tag

The following code:

<hst:headContribution category="jsFlag">
<script>
$(document).onload(function()

{ var jsflag = $('<input type="hidden" name="js_enabled" value="true"/>'); $('form').append(jsflag); }

);
</script>
</hst:headContribution>

and:
<hst:headContributions categoryIncludes="jsFlag"/>

results in:
<script>
<input type="hidden" name="js_enabled" value="true"/>
</script>

Obviously this is not the desired result, because all java script has been removed.

The problem does not occur when the script-code is surrounded by CDATA tags, but it shouldn't be a problem without the CDATA-tags as well.