Never break the browsers back button. It’s one of Jakob Nielsen’s top design mistakes from 1999 and it still holds true over ten years later.
The back button is the web users fail-safe, it’s something they can draw comfort from when they’re lost in the depths of a website. I’ve observed many a test where users click the back button five times instead of clicking the ‘home’ link once to return to a site’s front page. They understand and trust completely where the back button is going to take them, or so they think.
Thankfully the practice of deliberately preventing a user from leaving your website by the blocking back button has all but ceased, however with the increase use of AJAX and flash it seems there is more and more opportunity to break the back button ‘accidentally’.
I recently contributed to a discussion on the UX-Exchange about relying on browser for navigation and judging by some of the responses, even the experts are not in total agreement. The question seems born out of the fact that technology breaks the back button, therefore should we create an alternative within a page.
When navigating a site the user is on a journey, they’re creating a mental path of where they have been, the back button allows them to traverse this mental path and start again if they took a wrong turn. Each turn on this journey is a click of the mouse, be that following a hyper link to another page or clicking a link to refresh a list of search results.
Until user behavior changes and the back button is no longer the third most used feature (behind hyper links and in-page buttons) we should do all we can to avoid breaking the back button, irrespective of the technology we’re using.