FieldSet is a grouping component with a content toggle feature. At the top, legend defines a caption and draws a box around the body content. The FieldSet example with toggleable feature would be as follows:

 <p-fieldset legend="PrimeNG" [toggleable]="true" [collapsed]="true">
   PrimeNG is a collection of rich UI components for Angular.
   PrimeNG is a sibling of the popular JavaServer Faces Component  
   Suite, PrimeFaces.
   All widgets are open source and free to use under MIT License.
   PrimeNG is developed by PrimeTek Informatics, a company with years 
   of expertise in developing open source UI components.
</p-fieldset>

The preceding definition of the FieldSet will be displayed as shown in the following screenshot:

Similar to the Panel component, FieldSet provides a custom legend through the p-header attribute (that is, the customized header content).

The FieldSet caption text is managed by the legend property, whereas toggle features are controlled by toggleable and collapsed attributes. There are two event callbacks named onBeforeToggle and onAfterToggle available for any custom logic implementation.