The web works best when nothing is ever deleted: because nobody likes clicking on a link to a website that no longer exists. But sometimes companies go out of business, servers crash, or the person responsible for publishing something to the web has second thoughts.
But future versions of Firefox may help you put the web back together in your browser. Mozilla has launched an experimental “No More 404s” to detect when the page you’re visiting is showing a 404: Not Found error message… and then it lets you visit the Internet Archive’s Wayback Machine to view the last-saved version of that website, if there’s one available.
In order to try out No More 404s, you’ll need need to install the Test Pilot add-on for Firefox on a Windows, OS X, or Linux system. Once installed, a new button will show up in your toolbar. Click it to choose the experimental features you want to test.
No More 404s requires Firefox 48 or later to work.
There are third-party add-ons that offer similar functionality. But Mozilla’s Test Pilot program provides users with an early look at features Mozilla is thinking about baking directly into future versions of Firefox, no add-ons or extensions required.
In other words, if Mozilla receives enough positive feedback about No More 404s, it could eventually become a standard feature of the web browser. On the other hand, if users don’t like it or find it too buggy, Mozilla may fix or scrap the feature.
Right now No More 404s seems a bit hit or miss. Sometimes it fails to detect 404 pages at all, and if there’s no archived version of the page you’re hoping to visit, it doesn’t really provide much value.
Still, it’s nice to imagine a future where you can surf the web without encountering Page Not Found errors (or at least being able to resolve the issue with a single click).
Like most of the things Mozilla does, the No More 404s feature is open source. You can find the code at Github.