Sets the headers for caching for 10 days with JavaScript content type.

function cache_javascript_headers() {
	$expiresOffset = 10 * DAY_IN_SECONDS;

	header( 'Content-Type: text/javascript; charset=' . get_bloginfo( 'charset' ) );
	header( 'Vary: Accept-Encoding' ); // Handle proxies.
	header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', time() + $expiresOffset ) . ' GMT' );
}