<script>
Specifies a block of client-side scripting logic in JavaScript.
Syntax
<script
src="URI"
charset="string"
fetchhint="prefetch"|"safe"
fetchtimeout="time_interval"
maxage="time_interval"
maxstale="time_interval"
srcexpr="js_expression"
>
Script Text
</script>
Description
Scripts do not have their own scope, but are executed in the scope of the containing element.
| Attribute |
Description |
src
|
URI of the script. Optional (as alternative to inline).
|
charset
|
Character encoding of the script if src is used. Optional.
|
fetchhint
|
Specifies whether the interpreter can attempt to optimize dialog interpretation by prefetching the resource. See Prefetching Resources. Optional.
|
fetchtimeout
|
Specifies the interval to wait for the resource to be returned before throwing a error.badfetch event. See Handling Fetching Delays. Optional.
|
maxage
|
New in VoiceXML 2.0. Specifies the maximum acceptable age, in seconds, of the cached resource. See Maximum Age. Optional.
|
maxstale
|
New in VoiceXML 2.0. Specifies the maximum acceptable time, in seconds, during which an expired cached resource can still be used. See Maximum Stale Time. Optional.
|
srcexpr
|
JavaScript expression that evaluates to grammar file URI. Optional (as alternative to src or an inline grammar).
If you specify this attribute, the element cannot have content.
|
(VoiceXML 1.0 only) The following attributes can be used in applications in which the version attribute of the <vxml> tag is set to 1.0.
| Attribute |
Description |
caching
|
VoiceXML 1.0 only. Specifies the caching policy for the resource being fetched. See Caching. Optional.
Used in place of the VoiceXML 2.0 attributes maxage and maxstale.
|
|
|
Tips:
|
| • | Inside a <script> element, if your JavaScript script contains any of the characters "<", ">", or "&", that character must be escaped. The easiest way to do this is to place the entire script inside a CDATA section, as in: |
<script>
<![CDATA[
function factorial(n) {
return (n <= 1) ? 1 : n * factorial(n-1); }
]]>
</script>
|
|
| • | Remember that any variables or functions declared in a script are valid only within the scope that contains the <script> element. Define the script in document scope (in the <vxml> element) if it defines items that you want to use in several dialogs or blocks. Any items defined by a script inside a block are accessible only within that block. In the following example, the first block contains a script that defines the function foo. That function can be used in a JavaScript expression later in the same block. However, it is illegal to use the function in a different block. The <value> tag in the second block will fail because the function foo goes out of scope when the interpreter leaves the first block. |
<block>
<script>
<!{CDATA[
function foo() { return 1; }
]]>
</script>
<!-- This use of foo() is legal -->
Foo is <value expr="foo()"/>
</block>
<block>
<!-- ERROR!!!! This use of foo() is illegal -->
Foo is <value expr="foo()"/>
</block>
|
Usage
See Also
Examples
Example 1--script to get the current time:
<?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">
<form id="form">
<block name="time"> <!-- This block uses a java script to tell you the
time-->
<var name="hours"/>
<var name="minutes"/>
<var name="seconds"/>
<script>
var d=new Date();
hours=d.getHours();
minutes=d.getMinutes();
seconds=d.getSeconds();
</script>
<prompt>
The time is now <value expr="hours"/> hours
<value expr="minutes"/> minutes, and
<value expr="seconds"/> seconds.
</prompt>
</block>
</form>
</vxml>
Example 2 script that defines a factorial function:
<?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">
<property name="universals" value="help" />
<script>
<![CDATA[
function factorial(n) { return (n <= 1) ? 1 : n * factorial(n-1); }
]]>
</script>
<var name="max" expr="10"/>
<form id="form-factorial">
<field name="fact" slot="num" type="number">
<prompt>
Tell me a number and I'll tell you its factorial.
</prompt>
<catch event="help">
<prompt>
Please say a number more then zero and less than <value expr="max"/>
</prompt>
</catch>
<filled>
<if cond="fact < max">
<prompt>
<value expr="fact" /> factorial is
<value expr="factorial(fact)"/>
</prompt>
<else/>
<prompt>
Please choose a number less than <value expr="max"/>.
</prompt>
<clear namelist="fact" />
</if>
</filled>
</field>
</form>
</vxml>
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