code: https://drive.google.com/open?id=1yh4IOWx9YUVxVXfyFdNOIFhje_YXOGe1 demo : https://tieuphongoccho.000webhostapp.com demo 2: https://codepen.io/himalayasingh/full/QZKqOX, function(){ // chờ tí cho nó load nhạc nha ☺ }