Google plans to add a feature to the Chrome web browser that will prevent advertising slots on a website from triggering automatic file downloads in users browsers.

"We plan to prevent downloads initiated from ad frames that lack a user gesture to prevent unwanted drive-by-downloads. Download doesn't make much sense with ads. It happens very rarely in practice and is also difficult to reproduce, which implies that a very small amount of ads are doing automatic downloads. Blocking download in ad frames without user gesture will make the web less abusive and more secure," Google developers said in a Chrome browser status page.

This security feature is only valid if users don't interact with the ad frames.

Google defines an "ad frame" as "an iframe marked as ad by the Chromium ad detection infrastructure AdTagging."

Back in January, Google announced that Chrome would also block automatic file downloads (drive-by downloads) initiated from sandboxed iframes --a type of HTML iframes also used for showing ads, but also by exploit kits to plant malware on users' computers.

Google didn't say when it plans to start blocking automatic file downloads initiated from ad slots.