A JavaScript-to-native bridge is an interface that lets code running in a web view or embedded browser call functions in the host application or device environment. It is common in hybrid apps, where web content needs access to native features such as file handling, clipboard access, notifications, sensors, or system commands.
In cyber security, this bridge is important because it can turn ordinary web content into privileged app logic. If an attacker can influence the loaded page, inject JavaScript, or tamper with remote content, they may be able to trigger native actions that the browser normally could not perform. Defenders watch for overly broad bridge methods, weak input validation, and remote content loaded inside trusted apps. Safer designs restrict which functions are exposed, require explicit user consent, and treat every bridge call as untrusted input.