showNumberSpinner( )

Shows the number spinner for a numeric text input.

The showNumberSpinner() function returns a Promise when the number spinner for a numeric text input element is shown. A numeric text input element is a text input that has the inputType property set to 'number'.
Calling showNumberSpinner() sets the numberSpinnerHidden property to false.

The spinner allows site visitors to increment and decrement the numeric value of the text input.