Just CSS. Absolutely NO jQuery/javascript or any other programming language.
A simple CSS stop watch that can show the time taken up to 9999.99 seconds in .01 second intervals.
This has a START and STOP function where you can start the timer and stop it at any point, and then continue the count.
You can also start and stop the timer and then reset it back to zero.
This uses just one keyframe to animate each value and has a method of resetting the keyframe animation at any point using just CSS.
The stylesheet for this demonstration is in the page head, but if you use this, please keep my copyright comment with the stylesheet.