The <a4j:actionparam> component combines the functionality of both JSF <f:param> and <f:actionListener> and allows to assign the value to the property of the manager bean directly using the assignTo attribute.

The component <a4j:actionparam> is a combination of the functionality of two JSF tags: <f:param> and <f:actionListener> .

At the render phase, it's decoded by parent component ( <h:commandLink> or like) as usual. At the process request phase, if the parent component performs an action event, update the "value" specified in the "assignTo" attribute as its "value" . If a "converter" attribute is specified, use it to encode and decode the "value" to a string stored in the html parameter. To make the "assignTo" attribute usable add the actionParam instance to the parent component as an action listener.

<a4j:actionparam> has a "noEscape" attribute. If it is set to "true", the "value" is evaluated as a JavaScript code.

Example:

...

<script>

    ...

    var foo = "bar";

    ...

</script>

...

<a4j:actionparam noEscape="true" name="param1" value="foo" assignTo="#{bean.prop1}" />

...

The <a4j:param> extends <f:param> , so the "name" attribute is mandatory. Otherwise, the "value" misses due missing the request parameter name for it.

Table of <a4j:actionparam> attributes.

Visit the ActionParamter page at RichFaces LiveDemo for examples of component usage abd their sources.

More information can be found on the Ajax4jsf Users Forum.

More information about <f:param> and <f:actionListener> can be found in Sun JSF TLD documentation.