If a checkbox is selected how to make a text field required

Question

Hi
I hoping someone out there can help me.
I am creating a form in adobe acrobat 9, I have a checkbox called 'other' and a text field named 'other_please_specify'. What I am hoping to do is when a user selects the 'other' checkbox the 'other_please_specify' text field becomes required. I will also need some sort of action that if a user deselects the 'other' checkbox then the 'other_please_specify' text field is no longer mandatory.
Can anyone help me figure this out?
Thanks in advance

Answer 1

If by required you mean the required property of the field, the Mouse Up script of the check box can be something like:
(function () {
    // Get a reference to the text field
    var f = getField("other_please_specify");
    // Set the required property depending on the check box state
    if (event.target.value !== "Off") {
        f.required = true;
    } else {
        f.required = false;
The "if" block can be simplified to:
    // Set the required property depending on the check box state
    f.required = event.target.value !== "Off";