Developed initial Keyboard Lock support within the Fullscreen API for the achristensen07/WebKit repository, introducing a browser-level keyboard lock mode that modifies Escape key behavior during fullscreen sessions. This feature was implemented using JavaScript, HTML, and C++, leveraging Browser API and event handling expertise to enhance security and user control in fullscreen experiences. The work included creating targeted tests to verify the new keyboard lock functionality and integrating it with existing fullscreen handling logic. By laying the foundation for more predictable fullscreen interactions, this contribution addressed both user experience and security considerations while enabling future refinements to fullscreen API behavior.