ui:id

Generates an id that is unique within the request.

<f:variable name="triggerId" value="{ui:id()}" />

The id starts with the prefix (f by default) and is wrapped in «», for example «fq7Zr2LpA1». Use it when two components share an element and have to agree on its id, as the collapsible and the tooltip do in Composition. It is meant for ids in markup, not for secrets.