The Facet tag registers a named facet on the component associated with the enclosing tag. A facet represents a named section within a container component. For example, you can create a header and a footer facet for a dataTable component.

Example:

<h:dataTable id="reportTable" value="#{reportBean.dailyReport}" var="item">
  <h:column>
    <f:facet name="header">
      <h:outputText value="Daily Report" />
    </f:facet>
    <h:outputText value="#{item}" />
  </h:column>
</h:dataTable>

HTML Output

<table id="reportTable">
  <thead>
    <tr><th>Daily Report</th></tr>
  </thead>
  <tbody>
    <tr><td>Item 1</td></tr>
    <tr><td>Item 2</td></tr>
    <tr><td>Item 3</td></tr>
  </tbody>
</table>