Mitcsherlich

javascript原生+canvase，canvase图形可拖动，鼠标事件onmousemove、onmousedown、onmouseup。判断图形是否拖出指定的区域

使用鼠标绘制canvase图形functionmousedownHandler(event){if(event.button==0&&!flag){points.push({x:event.pageX-cvsClientRect.x,y:event.pageY-cvsClientRect.y});c