Critical Description
It is not possible to define a client side javascript function to be called after the element has been updated.
Something like: options=literal:
doesn't work because the method JSONObject#valueToString is always quoting all the elements of the json object. The output of the component is:
var suggest = new Ajax.Autocompleter(......, ......,
{.....,"afterUpdateElement":"myAfterUpdateElement",......});
But Ajax.Autocompleter expects a reference to a js function. Thats is the reason for the js error:
this.options.afterUpdateElement is not a function
[Break on this error] this.options.afterUpdateElement(this.element, selectedElement);