<link>

Description

A <link> element may have one or more grammars. The grammars are in the scope of the element containing this <link> element. When the user input matches one of the linked grammars, it activates the <link> to either throw an event, or transition to another document or dialog (i.e., form or menu).

Syntax


<link
    next="URI"
    expr="ECMAScript_Expression"
    event="event"
    eventexpr="ECMAScript_Expression"
    dtmf="DTMF_sequence"
    fetchaudio="URI"
    fetchaudiodelay="time_interval"
    fetchaudiominimum="time_interval"
    fetchhint="safe"
    fetchtimeout="time_interval"
    maxage="integer"
    maxstale="integer"
    message="string"
    messageexpr="ECMAScript_Expression">
  child_elements
</link>

Attributes

Attribute	Description
next	The URI of the dialog (i.e. form or menu) or document to transition to when the user input matches one of the link grammars. Exactly one of next, expr, event, or eventexpr must be specified.
expr	An ECMAScript expression to be evaluated and used as the URI of the dialog (i.e. form or menu) or document to transition to when the user input matches one of the link grammars. Exactly one of next, expr, event, or eventexpr must be specified.
event	The name of the event to be thrown when the user input matches one of the link grammars. Exactly one of next, expr, event, or eventexpr must be specified.
eventexpr	An ECMAScript expression to be evaluated and used as the name of the event to be thrown when the user input matches one of the link grammars. Exactly one of next, expr, event, or eventexpr must be specified.
dtmf	The DTMF sequence for this link. It is equivalent to a simple DTMF grammar. This attribute can be used at the same time as other grammars: the link is activated when user input matches either a link grammar or this DTMF sequence. Optional.
fetchaudio	The URI of audio to play while waiting for the document to be fetched. Optional.
fetchaudiodelay	The length of time to wait at the start of the fetch delay before playing `fetchaudio`. Optional.
fetchaudiominimum	The minimum length of time to play `fetchaudio`, once started, even if the document arrives in the meantime. Optional.
fetchhint	Defines when the next document should be fetched. Optional. safe - only load the next document when needed
fetchtimeout	The length of time to wait for the next document to be fetched before throwing an `error.badfetch` event. Optional.
maxage	Indicates that this document is willing to use a cached copy of the next document only while the age of the cached copy is less than or equal to the number of seconds specified by this attribute. Optional.
maxstale	Indicates that this document is willing to use a cached copy of the next document that has exceeded its expiration time by as much as the number of seconds specified by this attribute. Optional.
message	A message string providing additional context about the event being thrown. The message will be available as a variable within the scope of the `<catch>` element. Optional. (Can only be used if event or eventexpr is specified; only one of message and messageexpr can be specified.)
messageexpr	An ECMAScript expression to be evaluated and used as a message string, as documented under `message`, above. Optional. (Can only be used if event or eventexpr is specified; only one of message and messageexpr can be specified.)

Attribute Notes

The event specified by event/eventexpr is thrown based on the scope of the active dialog (ie. <field>,
<menu>, etc., where the user was when the link grammar was matched).

All attribute values that are ECMAScript expressions are evaluated based on variables from the scope of the active dialog (ie. <field>, <menu>, etc., where the user was when the link grammar was matched).

An error.badfetch event is thrown if more or less than one of next, expr, event, and eventexpr are specified.

Parents

Children

Extensions

Added fetchaudiodelay attribute.
Added fetchaudiominimum attribute.
Added <dtmf> as a child, to be used like <grammar>.

Limitations/Restrictions

None.

Example


<?xml version="1.0"?>
<vxml version="2.0" xmlns="http://www.w3.org/2001/vxml">
  <link event="goodbye" dtmf="*"/>
  <catch event="goodbye">
    Thank you for calling. Goodbye.
    <exit/>
  </catch>
  <form>
    <field name="field1" type="boolean">
      <prompt>Please press the star.</prompt>
    </field>
  </form>
</vxml>