How to call on function on select tag using option

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jQuery

How could i call on selected on an select tag den call on an function when something is selected from selected tag option

(function() {

        $("#CalenderListDrop option:selected").text(displayfreeTimeonLoad());


    }
);

I have tried like this but i dont work?


====================
UPDATE

$(document).ready(function () {

    var getListCalender = document.getElementById('CalenderListDrop');
    spHostUrl = decodeURIComponent(getQueryStringParameter('SPHostUrl'));
    context = new SP.ClientContext.get_current();
    parentContext = new SP.AppContextSite(context, spHostUrl);
    web = parentContext.get_web();
    var allLists = web.get_lists();
    context.load(allLists);
    context.executeQueryAsync(
            function () {

                var listEnumerator = allLists.getEnumerator();
                while (listEnumerator.moveNext()) {
                    var listName = listEnumerator.get_current();
                    var listTypeId = listName.get_baseTemplate();

                    if (listTypeId == SP.ListTemplateType.events) {

                        var array = new Array(listName.get_title());

                        for (var i = 0; i < array.length; i++) {

                            var opt = document.createElement("option");
                            getListCalender.options.add(opt);
                            opt.text = array[i];
                            opt.value = array[i];

                        }

                    }
                    break;
                }

            }

            ),
        function () {
            alert("Eror");

        };

}

);

UPDATE HTML
================

<select id="CalenderListDrop">
       </select>

<select id="LedigTiderDrop">
        </select>