What exactly do you want? The ScriptListener gives this code when the Copy CSS command is executed. This is it?
var d = new ActionDescriptor();
var r = new ActionReference();
r.putEnumerated(stringIDToTypeID("layer"), stringIDToTypeID("ordinal"), stringIDToTypeID("targetEnum"));
executeAction(stringIDToTypeID("copyLayerCSS"), d, DialogModes.NO);