P.S. for the project file above, simply run it and type - the text field is already auto selected (focussed) for you, so you can just start typing.
Ive added up to 10 positions for the cursor. You can add way more if you want, but I was just messing around for now.
Finally, if you open up the console window (press F12 when previewing the slide, then click the CONSOLE tab) , you will see some JS messages being shown which monitor the character count of the input field in realtime (using an eventListener)
Now.... how do we get it to play Doom 2?! :P