Forms and form items

Forms allow the user to provide voice or DTMF input by responding to one or more form items. The elements <field>, <subdialog>, <block>, <initial>, <record>, <transfer> and <object> are all form items.

Fields

Each field can contain one or more <prompt> elements that guide the user to provide the desired input. You can use the count attribute to vary the prompt based on the number of times that the prompt has been played.

Fields can also specify a type attribute or a <grammar> element to define the valid input values for the field, and any <catch> elements necessary to process the events that might occur. Fields may also contain <filled> elements, which specify code to execute when a value is assigned to a field. You can reset one or more form items using the <clear> element.

Subdialogs

The <subdialog> element is similar to a function call in a traditional programming language. It can be used to gather information and return it to the form. For more information, see Subdialogs.

Blocks

If your form requires prompts or computation that do not involve user input (for example, welcome information), you can use the <block> element. A <block> can also contain executable content such as <goto> or <submit>.

Types of forms

There are two types of form dialogs:

Machine-directed forms — traditional forms where each field or other form item is executed once and in a sequential order, as directed by the system.
Mixed-initiative forms — more robust forms in which the system or the user can direct the dialog. When coding mixed-initiative forms, you can use form-level grammars to allow the user to fill in multiple fields from a single utterance. You can use the <initial> element to prompt for form-wide information in a mixed-initiative dialog, before the user is prompted on a field-by-field basis. For more information, see Mixed-initiative application and form-level grammars.