HTML Node, Dynamic Selector

The HTML node information panel says:

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select string
if not configured in the edit panel the selector can be set as a property of msg.

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Question, How do I configure the sendor message property to send a selector string to the HTML node?

Alan

set msg.select in a change, function or template node.
e.g
In change node
set
msg. select
to the value
a/z (string) a

E1cid

That works. Thanks.

Alan