Unlike XUL or other component sets, there is no invalid XML element in the XHTML component set. ZK uses the org.zkoss.zhtml.Raw class for constructing any unrecognized XML element^[53]. Therefore, developers could use any tags that the target browser supports, no matter whether they are implemented as ZK components.

Similarly, you could use the Raw component to create any component not defined in the XHTML component set as follows.

new Raw("object"); //object could be any tag name the target browser supports