Bug 214254 Expose Javascript "event" object for interactivity
When doing interactivity with a chart, and specifying a Mouse Click event with an Invoke Script action, the browser event object should be passed into the script. This object should be named "evt", and accompany the other standard category and value series parameters.
chart/org.eclipse.birt.chart.device.extension/src/org/eclipse/birt/chart/device/image/JavaxImageIOWriter.java
}
		if ( bCallback )
		{
			
			return expr;
		}
		return JavascriptEvalUtil.transformToJsConstants( expr );
	}
	/**
	 * When 1). The action is supported, and the action type is INVOKE_SCRIPT.
	 * 2). The script has not been added into ImageMap. 3). The action acts on
	 * the value series area. Add the script into ImageMap.
	 * 
	 * @param sa
	 *            ShapedAction
	 * @param sb
	 *            StringBuffer
	 */
	private void userCallback( ShapedAction sa, StringBuffer sb )
	{
		addCallbackMethod( sa, sb, TriggerCondition.ONCLICK_LITERAL );
		addCallbackMethod( sa, sb, TriggerCondition.ONDBLCLICK_LITERAL );
		addCallbackMethod( sa, sb, TriggerCondition.ONMOUSEOVER_LITERAL );
		addCallbackMethod( sa, sb, TriggerCondition.ONFOCUS_LITERAL );
		addCallbackMethod( sa, sb, TriggerCondition.ONBLUR_LITERAL );
	}
	
	private void addCallbackMethod( ShapedAction sa, StringBuffer sb,
			TriggerCondition condition )
	{