LetterBoard is a TS/JS client side utility to open a customisable On Screen Keyboard (OSK) on any input or text box.
LetterBoard may not fully support TextAreas but the fix should be trivial.
First include both the JS and CSS files in your project
Simply add the initiator function to an onclick event from an input
<input type="text" onclick="openOSK(this);"/>
And then when the box is clicked, the keyboard should open (and close if you click in the corners of it)
It automatically brings the selected text field to the top of the screen and returns it once you are done typing.