Dynamic content usually consists of XFDL items whose appearance, operation, or value change at runtime in response to user events involving some other form element. If you are creating or modifying forms that will be used by people with special accessibility needs, you should only include dynamic content if it is essential to the operation of the form. This is particularly true if the dynamic items significantly affect the layout, appearance, or operation of the rest of the form.
Depending on its complexity, dynamic content can have a considerable effect on a form’s appearance and operation. Although dynamic content is often included to make forms easier to use, persons with visual or cognitive disabilities may not always be aware of these changes and may find the form difficult to understand, or may completely miss changes that affect the overall meaning of the form.
If you find that you must include dynamic content, you should make it as simple as possible. In addition, you should make every effort to alert users of how the form changes and which items are affected. The example section below demonstrates one way of doing this using acclabel items.
The following diagram shows part of a form containing some simple dynamic content. When users complete the "Quantity" and "Product" items, the form automatically fills in the "Unit Price" and "Amount" fields.
Although this is a simple example, the form should still identify which fields it updates automatically. The easiest way to do this is to include this information in the affected item's accessibility message. For example, the following code creates the accessibility message for the first "Amount" field:
Amount Column. Row 1. The form automatically calculates this amount.
Exceptions to this practice
Currently there are no exceptions to this practice.