Your every keystroke is recorded by over 480 of the most popular websites in the world

Researchers at Princeton University have found that over 840 globally popular websites are keylogging data and sending it to third-party servers. Some of the most popular and heavy-trafficked websites in the world were found running third-party scripts called "session replay" scripts, that can track users' every letter typed and every click and more which in turn were sent to third-party servers across the globe.

 The study's findings revealed that at least one of the firms' scripts is being used by 482 of the world's top 50,000 sites, according to researchers. The researchers say the scripts are often found on pages where users input their sensitive information, including passwords, credit card data and medical condition.

"These scripts record your keystrokes, mouse movements, and scrolling behavior, along with the entire contents of the pages you visit, and send them to third-party servers," the researchers said in a blog.

"Collection of page content by third-party replay scripts may cause sensitive information such as medical conditions, credit card details and other personal information displayed on a page to leak to the third-party as part of the recording," the researchers added. "This may expose users to identity theft, online scams, and other unwanted behavior. The same is true for the collection of user inputs during checkout and registration processes."

Fortunately, users can block session replay scripts using the popular ad-blocking tool AdBlock Plus. As a result of the revelations brought to light by the Princeton University researchers, AdBlock Plus issued an update to block all session replay scripts.