I did split off the topic to a new thread.
There are only two methods to update a page dynamically:
1) a <meta> tag with <meta http-equiv="Refresh" content="300" /> causes the browser to reload the entire page (and only the entire page) every 5 minutes.
2) an AJAX script can update part of the page at an interval based on dynamically loading some content and rewriting the HTML contents of the displayed page in the browser. That's what the ajaxXXwx.js script does for various data items based on the weather-software's realtime file.
For Atom Alerts, it's a bit more complicated and depends on which script you're using (atom-alerts, atom-top-warnings, nws-alerts) -- they all produce HTML which is displayed when PHP includes them in the page. The warning data itself is only updated at 5 or 10 minute intervals on the alerts server, so a 'realtime' partial update of the page wouldn't be more meaningful (or current) than just using a <meta> page refresh every 5 or 10 minutes (IMHO).