Recently with the advent of smart devices, various educational apps are being developed for smart learning. However, the existing native apps to run on a particular device, the device is not compatible. A new way to develop apps, webapp written using the HTML5 has the advantage of cross-platform support. We developed the webapp using HTML5 for learning lever in elementary school science curriculum. We conducted an expert evaluation for the web app of educative usability. The expert group was comprised of elementary school teacher. In result, it was evaluated lever learning content and webapp have high educational value.