Sets or gets the value of the selected option.
Setting the value property sets the options property's value
to be the selected option. You must set the value
property to a value that exists in the options list.
To reset the mobile picker to have no options
selected, set the value property to an empty string, null or undefined.
Getting the value property returns the value of
the currently selected option. If no value is selected, the
value property returns an empty string.
Notes:
value in code does not trigger an onChange event.value property returns the first selection. To get all the selected options, use the selectedIndices property.