*[Tor Browser](https://www.torproject.org)* is a web browser based on [Mozilla Firefox](https://www.mozilla.org/firefox/) but configured to protect your privacy.
That is why JavaScript is enabled by default but *Tor Browser* disables all potentially dangerous JavaScript. We consider this as a necessary compromise between security and usability.
<p>To understand better the behavior of <i>Tor Browser</i>, for example, regarding JavaScript and cookies, you can refer to the <a href="https://2019.www.torproject.org/projects/torbrowser/design/"> <i>Tor Browser</i> design document</a>.</p>
You can change the security level of *Tor Browser* to disable browser features as a trade-off between security and usability.For example, you can set the security level to *Safest* to disable JavaScript completely.
