<throw>

Throws an event.

Syntax

 <throw
     event="event"
     eventexpr="js_expression"
     message="string"
     messageexpr="js_expression" 
 />

Description

You can throw either a predefined event or an application-specific event. For more information, see Chapter 3, Event Handling.

Attribute Description

event
Event to throw. Optional (as alternative to eventexpr).

eventexpr
New in VoiceXML 2.0. JavaScript expression that evaluates to the event to throw. Optional (as alternative to event).

message
New in VoiceXML 2.0. Message string providing additional context about the event being thrown. Optional.

messageexpr
New in VoiceXML 2.0. XML expression that evaluates to the message string. Optional.

One and only one of the attributes event or eventexpr must be specified. At most one of the attributes message or messageexpr may be specified.

Within an event handler that catches the thrown event, the variable

Tip:

•	If a JavaScript expression contains any of the characters "`<`", "`>`", or "`&`", that character must be replaced with the corresponding escape sequence "`<`", "`>`", or "`&`". For more information, see JavaScript Quick Reference.

Usage

Parents Children

<bevocal:foreach> <block> <catch> <error> <filled> <help> <if> <noinput> <nomatch>
None.

See Also

•	VoiceXML 2.0 Specification: `<throw>`
•	Related tags: `<catch>`, `<error>`, `<help>`, `<noinput>`, `<nomatch>`, `<rethrow>`

Examples

See other catch and throw examples under <catch> and <rethrow>.

 <?xml version="1.0" ?>
 <!DOCTYPE vxml PUBLIC "-//BeVocal Inc//VoiceXML 2.0//EN"
  "http://cafe.bevocal.com/libraries/dtd/vxml2-0-bevocal.dtd">
 
 <vxml version="2.0" xmlns="http://www.w3.org/2001/vxml">
   <catch event="myEvent">
     <prompt>
       Catch of my event at document scope.
       But here the value of my number has gone away. 
       It sounds like <value expr="mynumber"/>
     </prompt>
     <reprompt/>
   </catch>
   
   <catch event="nomatch noinput" >
     <prompt>
       Catch at document scope.
     </prompt> 
     <reprompt/>
   </catch>
 
   <property name="universals" value="help" />
   <help>
     <prompt>
       Catch for help at document scope.
     </prompt>
     <reprompt/>
   </help>
   
   <form id="numbers">
     <catch event="myEvent">
       <prompt>
         Catch of my event at form scope.
         <value expr="_message"/>
         The value of my number has not gone away.
         It sounds like  <value expr="mynumber"/>
       </prompt>
       <clear/>
       <rethrow/>
     </catch>
 
     <block name="numbergame"> This is a test of the throw tag. </block>
     <field name="mynumber" type="number">
       <prompt> 
         Tell me a number greater than ten. 
       </prompt>
       <filled>
         <if cond="mynumber &lt; 10">
           <throw 
             event="myEvent" 
             messageexpr="mynumber + ' is less than ten'"/>
         <elseif cond="mynumber &gt; 10" />
           <prompt>
             You said <value expr="mynumber"/>
           </prompt>
         <else/>
           <throw event="myEvent" message="Ten is not greater than ten"/>
         </if>
       </filled>
     </field>
   </form>
 </vxml>

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Attribute	Description
`event`	Event to throw. Optional (as alternative to `eventexpr`).
`eventexpr`	New in VoiceXML 2.0. JavaScript expression that evaluates to the event to throw. Optional (as alternative to `event`).
`message`	New in VoiceXML 2.0. Message string providing additional context about the event being thrown. Optional.
`messageexpr`	New in VoiceXML 2.0. XML expression that evaluates to the message string. Optional.

Parents	Children
`<bevocal:foreach>` `<block>` `<catch>` `<error>` `<filled>` `<help>` `<if>` `<noinput>` `<nomatch>`	None.