A "browser fingerprinting script" is a piece of JavaScript code that runs inside a web page and works by testing the presence of certain browser functions.
Today, "browser fingerprinting" is commonly used by online advertisers as a tracking tool for next-generation users. Advertisers run different types of fingerprint functions, creating one or more "fingerprints" for each user and then using them to track the user as he / she has access to other websites on the internet.

Due to the intrusive way in which online advertisers currently use "browser fingerprinting", many browser makers such as Firefox, The Chrome, The Opera, Brave and Tor Browser, have developed functions to detect and block these types of malicious code.
10% of the TOP 100,000 Alexa websites use "fingerprinting scripts"
In an academic journal published earlier this month, a team of academics from the University of Iowa and the University of California analyzed how popular "browser fingerprinting scripts" are used by webmasters.
Using a machine learning tool kit they developed and named FP-Inspector, scanned and analyzed the top 100.000 most popular websites on Internet, according to Alexa ranking.
"We find that browser fingerprinting exists in more than 10% of the top 100.000 websites," the research team said.
However, the research team also points out that despite the large number of sites currently using browser fingerprinting, not all scripts are used for tracking. Some fingerprinting scripts are also used for tracking fraud, as automated bots tend to have the same or similar fingerprints and fingerprinting scripts are a reliable method for detection their.
However, the research team also analyzed what browser or JavaScript API features the scripts that they were trying to capture.
"What we found is that browser fingerprinting scripts usually do not use a single technique (eg, fingerprinting on canvas), but combine many techniques together," the researchers said.