{optgroup-label}
{option-label}

If the user has a pointing device (e.g., mouse):

  1. Hold shift to select two items along with all those in between
  2. Hold Cmd (Ctrl on Windows) to select multiple items
  3. Hold Cmd (Ctrl on Windows) to deselect item
  4. Up/Down arrow keys to move the selection
  5. Hold Cmd (Ctrl on Windows) + up/down arrow keys to move the focus, press spacebar to select focused element

Touch devices:

  1. Select options behave like checkboxes