What is a browser cache?
Last month we explained what browser cookies are and this month we’re looking into its partner – the browser cache. When you browse the internet, your browser will automatically download certain files from websites to your computer as it is generally quicker for your browser to grab these again from your PC's hard drive, than to re-download them from the internet every time you navigate to a new page. For example, when you visit a website, some images, HTML and CSS code (the files which control how the website works and looks) are stored on your computer so that they do not have to be re-downloaded every time you refresh or change page. This is useful because it speeds up browsing, creating a more enjoyable user experience. It’s especially important on mobile devices, which often rely on slower mobile data connections.
The length of time cache files are stored for is determined by the website they come from, and can vary from a few days up to a year. Understandably, some users don’t like the idea of files from other websites being stored on their personal computer, however, you can always manually empty your browser cache whenever you want to. It's also important to have up-to-date antivirus software and an active firewall, whilst only visiting websites you trust, to help mitigate any risk of your computer caching malicious files.
When a cache is doing its job successfully, you generally won't notice anything at all. However, occasionally you may notice something looks messy or out-of-date, which could indicate your browser is caching old data and needs to be emptied. For example, this could be because an older image is saved in your cache and has loaded this instead of the newer one. If this happens, you can press Ctrl+F5 on your keyboard for PC or Cmd+R for Mac, which should refresh the page and the cache for it too. Alternatively, you can clear your entire browser cache by going into the settings and clearing them from there. These links can help you find out how to do this for Chrome, Firefox, Edge and Safari.