У вашего броузера проблема в совместимости с HTML5
Teachers take note -- here's an affordable app that is good for lots of fast, multiple-choice-style practice related to visual counting and classification. You get sets of hand drawn shapes, good record keeping, and a feedback system that asks you to fix your mistakes (going beyond the typical "right and wrong." Note however that the format never strays from "touch the right answer" interaction style.