HTML5 is an evolution of the HTML standard that aims to improve web applications and make them more responsive. It introduces several new elements and features such as canvas for drawing graphics, video and audio elements, local storage, and APIs to take advantage of multi-core CPUs and new parallelism architecture. The development of HTML5 was a collaboration between the W3C and WHATWG to build on existing standards like HTML, CSS, DOM and JavaScript. It simplifies syntax and reduces the need for plugins like Flash. Browser support for HTML5 features continues to improve across all major browsers.