Google will soon penalize sites that hijack your browser’s back button

Have you ever tried to click “back” on a website, but instead of returning to the previous page you ended up on a wall of ads? This can happen when websites or advertising networks use JavaScript to alter your browser’s history. It’s especially common in mobile browsers.

In a recent Google Search Central blog post, the company says that this type of “back button hijacking” is growing increasingly prevalent and wants to do something about it. Back button hijacking is now a codified violation in its spam policy, which comes into effect on June 15th.

Google defines back button hijacking like this:

When a user clicks the “back” button in the browser, they have a clear expectation: they want to return to the previous page. Back button hijacking breaks this fundamental expectation. It occurs when a site interferes with a user’s browser navigation and prevents them from using their back button to immediately get back to the page they came from. Instead, users might be sent to pages they never visited before, be presented with unsolicited recommendations or ads, or are otherwise just prevented from normally browsing the web.

And explains why tackling this is important:

We believe that the user experience comes first. Back button hijacking interferes with the browser’s functionality, breaks the expected user journey, and results in user frustration. People report feeling manipulated and eventually less willing to visit unfamiliar sites. As we’ve stated before, inserting deceptive or manipulative pages into a user’s browser history has always been against our Google Search Essentials.

Websites now have two months to remove all scripts that manipulate users’ browser histories and must also ensure that any libraries or ad platforms they use don’t hijack the back button. Sites that violate this new policy may, among other things, be penalized with a lower ranking in Google’s search results.