def auto_complete_field(field_id, options = {})
function = "new Ajax.Autocompleter("
function << "'#{field_id}', "
function << "'" + (options[:update] || "#{field_id}_auto_complete") + "', "
function << "'#{url_for(options[:url])}'"
js_options = {}
js_options[:tokens] = array_or_string_for_javascript(options[:tokens]) if options[:tokens]
js_options[:callback] = "function(element, value) { return #{options[:with]} }" if options[:with]
js_options[:indicator] = "'#{options[:indicator]}'" if options[:indicator]
{:on_show => :onShow, :on_hide => :onHide, :min_chars => :min_chars}.each do |k,v|
js_options[v] = options[k] if options[k]
end
function << (', ' + options_for_javascript(js_options) + ')')
javascript_tag(function)
end