In case you needed any more convincing, here's yet more proof that nothing you do on the Internet is truly private.  Reports today have warned of a feature of HTML5 that allows for the tracking of browsers online, without the phone user's knowledge. According to The Guardian, the feature in question allows websites to see how much battery power a visitor has left on their device. The battery status API applies to Firefox, Opera and Chrome browsers, and is designed to help websites conserve batter power -  the logic being that when a browser is low on power, the site or app can switch to a low-power mode. The World Wide Web Consortium, or W3C, which oversees the development of web standards, approved the API in 2012, saying: "The information disclosed has minimal impact on privacy or fingerprinting, and therefore is exposed without permission grants". However new research has shown that the information is a lot more specific than first assumed. In The leaking battery A privacy analysis of the HTML5 Battery Status API, authors Lukasz Olejnik , Gunes Acar , Claude Castelluccia  and Claudia Diaz warn: "In short time intervals, Battery Status API can be used to reinstantiate tracking identifiers of users, similar to evercookies. Moreover, battery information can be used in cases where a user can go to great lenghts to clear her evercookies. In a corporate setting, where devices share similar characteristics and IP addresses, the battery information can be used to distinguish devices behind a NAT, of traditional tracking mechanisms do not work."