Weblog (or Blog)
Monday, April 02, 2018
If a frequently updated web page that you visit does not appear to change between visits, your browser may be loading an older version from your browser cache. If you also use a publicly-available computer, such as at a library, to access a secure site, some of your information may remain recorded on that computer when you stop using it. To remedy these situations, you may need to clear your browser cache. This post tells you how.
Most of us use one of the major modern browsers to access the Internet: Chrome, Internet Explorer, Firefox, Opera, Safari, or Edge. We also know that sometimes we need to refresh or reload a web page to make sure we are viewing the most up to date version. All of those browsers have the same icon to refresh or reload a page: a broken circle with an arrowhead on one side of the break. Click that and the page reloads. You can also refresh the page with a keyboard shortcut: F5 for the Windows browsers and Command and R keys pressed simultaneously for Mac browsers. But sometimes when you refresh a page that you know has been recently updated, the displayed content does not change. What's up with that? The culprit is the browser cache.
The Internet truly is an amazing thing. Using it, you can sit in your den and read a web page on a computer anywhere in the world. Click on a link in your browser and communications between your browser and the web page begin at, literally, the speed of light. Usually in a matter of seconds, the browser and server (the computer on which the web page resides) talk to each other multiple times to establish that you want to look at a specific page (specified by the link), that the server is who it says it is, and that everything is in place for the server to send all the text, graphics, and videos on the page to your browser, which displays the web page. Amazingly fast. But what if it could be faster?
That's where the cache comes in. The cache is a file on your hard drive that saves all the communications between your browser and the server. Even though the Internet is fast, it is not as fast as retrieving text, graphics, or videos from your hard drive. If you revisit a web page, your browser first checks to see if the information for that page is in the cache. If it is, it loads the page from there and delivers the web page to your screen. The page will be loaded faster than if it was loaded from the server on the Internet.
The problem occurs when the information on the Internet server has changed, but the version in your cache has not. Then, even if you reload the page, it reloads the unchanged version from the cache. So you don't see the changes on the server. The way to resolve this is to delete the version in your cache. This is called clearing the cache. When you click on the page's link after clearing the cache, the page as it exists on the server downloads to your browser. Clearing the cache is done from within the settings of your browser. Each browser has a slightly different way to do it. Here is an article that tells you how to clear the cache in all the major browsers.
You want to be careful what you clear from the cache. As noted above, all the communications between the server and your browser are stored in the cache. This includes cookies, passwords, and your browsing history (a list of all the web pages you have visited). You probably do not want to delete some of that information from your cache as it includes information that you will have to reenter. Each browser allows you to select what information you delete (clear) from the cache. For the outdated web page, you should selectively delete information labeled "page data" or "images and files" or "temporary Internet files." You will then be assured of getting the most recent version of the web page downloaded to your browser.