A browser-based event display for the CMS Experiment at the LHC using WebGL

Modern web browsers are powerful and sophisticated applications that support an ever-wider range of uses. One such use is rendering high-quality, GPU-accelerated, interactive 2D and 3D graphics in an HTML canvas. This can be done via WebGL, a JavaScript API based on OpenGL ES. Applications delivered via the browser have several distinct benefits for the developer and user. For example, they can be implemented using well-known and well-developed technologies, while distribution and use via a browser allows for rapid prototyping and deployment and ease of installation. In addition, delivery of applications via the browser allows for easy use on mobile, touch-enabled devices such as phones and tablets. iSpy WebGL is an application for visualization of events detected and reconstructed by the CMS Experiment at the Large Hadron Collider at CERN. The first event display developed for an LHC experiment to use WebGL, iSpy WebGL is a client-side application written in JavaScript, HTML, and CSS and uses the WebGL API three.js. iSpy WebGL is used for monitoring of CMS detector performance, for production of images and animations of CMS collisions events for the public, as a virtual reality application using Google Cardboard, and asa tool available for public education and outreach such as in the CERN Open Data Portal and the CMS masterclasses. We describe here its design, development, and usage as well as future plans.