Don't use the decapitated (deprecated) language attribute. You can just doc write it out.
Code:
<script type="text/javascript">
if (Daynumber>10)
document.write('<script type="text/javascript" src="archivLINES.js"><\/script>');
</script>
You could use the DOM, but that gets a bit complicated and isn't supported well for script tags.
A better approach would be to have your function that actually does the work check this, ex:
Code:
function archive_lines(){
if (Daynumber<11)
return;
. . .
doing nothing if the value is less than 11.
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