I'm working on a web form which allows the user to enter a 1) single number or 2) range of numbers in a text input field.
Problem: I need to communicate to the user that a range is allowed within this text input field (e.g. 1-4; 5,6,7). There may be more than one field on the page where the user can enter a range.
Does anyone have any supported research with labeling such fields in a way that is immediately clear for the user? I'm considering a few untested methods, but I'm wondering if anyone has any quick and dirty research on this.