If you continue clicking on play it will play it again over the previous one. Don't go crazy clicking, lest you crash your browser. I think the correct behaviou

If you continue clicking on play it will play it again over the previous one. Don't go crazy clicking, lest you crash your browser. I think the correct behaviour would be to stop the previous script run and start over. No, I don't know enough javascript to fix it myself and create a pull request, in case you're wondering. ;)