Definition: "Flash.js" is a modern JavaScript framework for web applications, often used in conjunction with HTML5 or CSS3 to create dynamic content on the client-side of a website. Definition: Flash.js is a framework that enables developers to write JavaScript code directly within HTML and can be used with other JavaScript frameworks. It provides built-in support for HTML5 and CSS3 technologies, allowing developers to create interactive elements such as flash effects, animations, and game-like functionality.