Syntax:

any_valid_fragment

[Optional][Default: depends on device]

It specifies the message that will be displayed if the client doesn’t support this device.

<device-config>
    <device-type>ajax</device-type>
    <unavailable-message><![CDATA[
<p style="color:red">Sorry, JavaScript must be enabled in order for you to use KillApp.</p>
    ]]></unavailable-message>
</device-config>