Using PDF, is it possible to create a single form element with multiple fields of which several can be selected? For example, in HTML, one can create a set of checkboxes associated with the same field name:
<div>Select one for Member of the School Board</div>
<input type="checkbox" name="field(school)" value="vote1">
<span class="label">Libby T. Garvey</span><br/>
<input type="checkbox" name="field(school)" value="vote2">
<span class="label">Emma N. Violand-Sanchez</span><br/>
In this case, the field name is “field(school)”, and when the form is submitted, “field(school)” can be supplied 0, 1, or 2 times.
Is there an equivalent construct in PDF where a single field can have multiple values. So far in my investigation, it appears that if fields are assigned the same name, it is only possible to select one field. If it is possible to implement this in PDF, what is this construct called and how can it be implemented?
Edit: To clarify, I am aware that a PDF can contain multiple form fields with different field names, and those can be selected independently, but then the grouping is implicit and not explicit as with the HTML form. I would like to use a construct that makes the grouping of options explicit, and preferably allows for restrictions (e.g. at least one required, no more than 2 allowed, etc).
Edit: If someone can find an authoritative opinion that this is not possible, that would also be a desirable answer.
asnyder’s response led me to the conclusion that there is no automatic way to handle multiple values within a single field (as one can with HTML). asnyder’s examples come from Developing Acrobat Applications Using JavaScript, available from the Acrobat Javascript Developer Center. This document provides some examples of how to manipulate checkboxes, combo boxes, and radio buttons. All of the examples shed some light on the problem and ultimately led me to the conclusion that any system that is using PDF forms will have any multi-selectable groups implicitly defined.
Using the construct of groupName.fieldName appears to be useful to manipulate the widgets as a group (in Acrobat Javascript), but the fields of a group cannot be enumerated (without enumerating all fields and filtering for the groupName), and the collective value of that group cannot be determined without programatically inspecting the values.
In other words, a multi-selectable value is not an intrinsic feature of Acrobat nor of PDF in any substantial way, though it is possible to implement such a form through programming.