Browser caching
Browser caching
Browser caching definition
Browser caching is a process where web browsers store copies of web pages, including text, images, and other content, on your device. This makes websites load faster the next time you visit them because the browser doesn’t have to download everything again.
See also: content delivery network, web cache poisoning, cache server, DNS cache, XSS
How browser caching works
- When you visit a website for the first time, your browser downloads all the files it needs to show the website, such as HTML, CSS, JavaScript, and images.
- The browser stores these files in its cache, a special directory on your device.
- If you revisit the same page, the browser checks its cache first. If it finds a cached version of the page or its elements, it loads these from the cache instead of downloading them again. That speeds up the loading process.
- Cached files have an expiration date set by the website. If a file in the cache is older than this date, or if the website has been updated since, the browser will download the new version and update the cache.
Security Issues of browser caching
- Cache poisoning. Hackers can manipulate cached data in cache poisoning attacks to spread malware or send users to fake websites.
- Cross-site scripting attacks. If a site caches user-generated content without proper security measures, it can suffer from XSS attacks.
- Data leakage. Cached data can have personal information, which others could access if your device is shared or compromised.