We update our Web pages frequently. Our home page has almost always been changed within the last three days, as indicated by the "last revised" date at the bottom.
Most Web browsers use disk caching to speed up your second access to files you have seen before. The page is saved on your hard disk or in memory of a machine. When you request it a second time by selecting a link you have used before, the file may come from the cache rather than being downloaded from the Internet. Ideally the browser checks to see if the page needs updating before it serves you a stale page. But not always.
The best way to check this is to change the domain in the page address in that white box at the top of your browser from helmets.org to bhsi.org and hit your enter key. You will get the same file from the same server, but changing the address fools the browser and cache into thinking it is an entirely new file. Or you can try to configure your browser to do that automatically:
In Internet Explorer you will find an option under Tools-Internet Options-General. In the Temporary Internet Files box, click on the Settings button. We use "every visit to the page" here. The Refresh button does not always work as advertised, and may continue to deliver the old page no matter what your settings are.
In Netscape there is a preference reached through Options-Network-Caching that lets you set an option for Verify Documents to Once per Session, Every Time, or Never. If yours is set to never, you are going to see stale pages frequently when you revisit a site. We recommend you set that option to at least Once per Session. On our own machines we set it to Every Time. It may slow page reloads a little, but to us it's worth the few second's wait. Netscape sometimes just reverts back to never on its own without telling you, so if you still have problems, you can set your cache size to zero bytes. At least that way exiting the program and reloading it will wipe the cache clean. The reload button sometimes works as it should and gets the new page. We wish Netscape would address this bug and give us a robust setting for cache options.
In addition to your browser, some organizations or Internet Service Providers also cache or save Web pages and supply them to the next one of their subscribers who tries to browse them as a way of saving Internet bandwidth and making the page load faster. AOL is a prime example. The page is saved on a disk or in memory of a machine within the organization. This permits many hits to be served from one occasional download of the page by the organization's server. Sometimes we have updated pages and had browsers complain that we have not. If your organization has a "proxy server" or another server that caches files, or if you are with AOL or another ISP who uses caching, you may well be seeing stale pages. Fast, efficient, but possibly stale. For some pages we do not update frequently, including this one, it will seldom matter, but for our WhatsNew page it can make a big difference. All of our pages have the Latest Update date at the bottom.
On some systems with caching, cached pages can be updated just by hitting your Reload or Refresh button. On others you may have to ask your system administrator how to update the cache. You can also use our alternate domain addresses:
http://www.bhsi.org gets you to the same page (file) on the
same physical machine as http://www.helmets.org
but the difference in the URL will fool the cache unless some other user has done it yesterday or last week.
If you suspect you are being victimized by cache problems, send us an email to
email@example.com telling us which page is in question and we will confirm the date of our latest revision.
Please note that this particular page is not frequently revised!
This page was last revised on: August 29, 2006.