This function is called when all the following are met: (New v18.0200)

An element is unknown (not in the configuration)

HTML custom elements are enabled

The element is a valid custom element name

This function can be used to display additional messages when certain unknown custom elements are used; the following variables are defined when this function is called:

$ouce_compatmsg - set to true or false; whether to generate the default compatibility message for this custom element if it's the first time it is used (default is true)

$ouce_element - the name of the unknown custom element

See also: onUnknownElementMessage(), onInactiveElementMessage()