I have a form like this:
The user must fill in the first or third field. They can also fill out two fields or all fields. Essentially they need to provide a link or comment for the form to submit.
How can I best explain this to the user before they submit? I could rely on validation after they submit but I'd prefer to find something intuitive from the get go.
I'd go this way:
Post an update
[Link]
[Comment]
[Movie] (Optional) – Gives an idea that other two are required, but not forcing to fill both of them
[Submit] – Disabled until link or comment is filled
Now I can't think of any error case, can you?
First thing, you need to group your alternative fields together. It will be a hassle for a user to move around back to the first field if he doesn't want to fill the third field. You should not move the user up and down the form for filling the details. It should be a top down approach. So I would suggest you to group your link and comments fields together.
Put the "What movie is it about?" first, followed by the two detail fields.
I would also suggest you place a small note before the two detail fields, like "At least one of the following two fields are required".
I also thought of using an 'OR' between two fields but it would look like that you need to fill only one out of the two and the user wont be compelled to fill both the fields.
I could not comment to the question since I am not reputable enough yet. It would make a difference if filling both fields creates additional value for you. Do you prefer the users to fill in both but you allow them to fill in only one or it is enough for you if you have one of the info.
