We have a central system that uses javascript to place an emergency notification message on all of our websites from one single location.
In your page's head:
<link rel="stylesheet" type="text/css" href="https://www.andrews.edu/css/andrews-ens.css" />
<script>jQuery.getScript('https://www.andrews.edu/code/js/ens.js');</script>
In the footer (instead of the base version's footer):
<script>
jQuery.getScript('https://www.andrews.edu/code/js/ens.js',
function(){
if( jQuery('#ens').length )
jQuery('#ens').addClass('custom-class');
}
);
</script>