fulfill="event-expr"fulfill="event-expr1, event-expr2, event-expr3"

where event-expr, event-expr1 and others are called event expressions. An event expression is used to identify a component. It can be one of the following formats:

event-nametarget-id.event-nameid1/id2/id3.event-name${el-expr}.event-name

It is used to specify when to create the child components. By default (i.e., fulfill is not specified), the child components are created right after its parent component, at the time the ZUML page is loaded.

If you want to defer the creation of the child components, you can specify the condition with the fulfill attribute. The condition consists of the event name and, optionally, the target component's identifier or path. It means that the child elements won't be processed, until the event is received by, if specified, the target component. If the identifier is omitted, the same component is assumed.

If an EL expression is specified, it must return a component, an identifier or a path.

Refer to the Load on Demand section for more details.