• Center element vertically and/or horizontally

Use 'margin-top: 50%%; margin-bottom: 50%%;' for vertical alignment
Use 'margin-left: 50%%; margin-right: 50%%;' for horizontal alignment
Use 'margin: 50%%;' to center element in the container

• What event handlers are available for the element

onMouse( e:Event ), onKey( e:Event ), onFocus( e:Event ), onScroll( e:Event ), onControlEvent( e:Event ), onTimer(), onSize()

All events are bubbling except onTimer and onSize

• How to define an event handler for an element?

<script>
type MyElementHandlerClass : Behavior {
    function onMouse(evt) {
          // handler code
    }
}
</script>

<div style="prototype: MyElementHandlerClass;" >my div content</div>

• How to send an event?

Use Element.postEvent( evtcode: int [, reason: int [, owner: Element ]] )

• How to send a custom event?

Use postEvent method of element to post an event and onControlEvent handler to handle custom user events.
User defined event types are in range 0x1000-0x7fff.