In general HTML5 is just next iteration of standards for web development in browser based environment (end client). Previously many advanced features like video playback, 2d/3d graphic, audio needed external plugins (Flash/Java) or browser specific extensions/coding, so that complicated cross platform app/page coding. Now with standards brought by HTML5 and it support from all web browser developers you can use one code base to have you site with same features on all modern browsers. Like for example Canvas for 2d graphics or WebGL for 3d stuff. It’s up to browser devs to have all such features to work properly.
Taking that into consideration, as MrPlow already specified, you should use JavaScript and one of many popular JS libs like Jquery, that have many webpage / app features already built-in. There is really ton of it, but I’m not an expert so can’t advise what would best fit your needs.
As development tools you can use for example VS Code / Brackets as editor, Xampp for server.