How to show Jquery UI autocomplete widgets on autocomplete() method? -

i'm hoping can this,
i'm having difficult time getting jqueryui's autocomplete work $.ajax({}) call in asp.net application.
can make ajax call, getting response service , list of locations.
but still autocomplete list not shown, when press down arrow key location list rendered on page.
should rendered/shown after getting list of locations web method. how possible?

i'm using autocomplete jquery site: http://jqueryui.com/demos/autocomplete/

sample code

function getcitieslikelist(objcity) {     var cities = "";         $.ajax({             type: "post",             url: http://localhost/testweb/location.asmx/getlocations,             data: "{ city : '" + objcity + "'}",             contenttype: "application/json; charset=utf-8",             datatype: "json",             success: function (msg) {                 if (msg.d != null && msg.d != "") {                     cities = "";                     cities = msg.d;                     $("#citilist").autocomplete({                         source: cities                     });                 }                 else                     $("#citilist").attr("autocomplete", "off")             },             error: function (xhr, ajaxoptions, thrownerror) { return false; }         });  } 

i found way trigger jquery ui autocomplete functionality, without typing box:

$('#field').autocomplete({     source: '/path/to/data',     minlength: 0 }); $('#button').click(function() {     $('#field').autocomplete('search', '') }); 

sending 'search' arg triggers search functionality. second argument "term" sent data handler @ /path/to/data.