It's ok to close the script tag then open it again, at least with the following example:
Code:
<script type="text/javascript">
//<![CDATA[
a = 2;
b = 3;
//]]>
</script>
<script type="text/javascript">
//<![CDATA[
c = a+b;
document.write("c: ", c);
//]]>
</script>
Output: