Make sure you click the 'refresh' button in your internet browser, so
that your computer can keep up with all the changes you are making.
If this doesn't work, your computer may have a caching issue. A 'cache' is basically where your web browser downloads temporary
internet files. This means if you visit a site you've been to in the
past; your internet browser recalls these files (normally images) and
rather than downloading them again, simply loads them from your hard
drive.
Clearing the cache forces the internet browser to re-download all of
the files on a website. So if you've made changes to your website but
haven't cleared the cache, sometimes, the browser will bring up
out-dated files.
You can force your web browser to get a fresh copy of your website by clicking reload/refresh.