Construct is great tool for people starting out making games. It's designed to let you create 2D games of almost any type. It has a set of modern tools to allow you to put your game together quickly, and you can build the logic of the game without then need for actual coding. It also has built-in "behavious" that allow you to get common game mechanics such as platform physics up and running instantly.
Construct 2 exports to HTML5 by default but there's a paid version that allow you to publish to iOS, Android and Desktop.