- this.selectedPiece.style.left = (e.clientX-this.start.x) + "px";
- this.selectedPiece.style.top = (e.clientY-this.start.y) + "px";
+ const [offsetX,offsetY] = !!e.clientX
+ ? [e.clientX,e.clientY] //desktop browser
+ : [e.changedTouches[0].pageX, e.changedTouches[0].pageY]; //smartphone
+ this.selectedPiece.style.left = (offsetX-this.start.x) + "px";
+ this.selectedPiece.style.top = (offsetY-this.start.y) + "px";