Delay between firing

Hi. My game is finished, publied (don't hesitate to play: Scirra arcade, Astro Adventure). But when playing on mobile, I found a bug that I absolutely don't know how to fix. It's when the player is touching the button to fire,if he hold it, it will fire an infinite line of bullets. How can I solve this problem ?

Use the search amongst the website and look for the keyword "Fire rate".

https://www.scirra.com/arcade/tutorial-games/shoot-left-and-right-with-firerate-1115

Thank you!