Stop clock actionscript help

It’s been a long time since I’ve visited, sorry in advance if anything

THE SITUATION:
I want to make a stop clock that starts on the touch of a button

Like using getTimer() but only starts the time at the click of a button

I do not want to display todays date but just a millisecond stopclock like on a watch, one that you can reset and time again

I hope you can understand that, I hope you can help