jquery ajax success function returns undefined variable -

i trying simple set variable results of jquery ajax call have set non synchronous.

all attempts far return undefined , don't know why.

i understand cannot use synchronous call code have moved on before results returned.

here's basic code:

$(document).ready(function() {     var test = visitordata();     console.info(test); }); 

and ajax call:

function visitordata() {  var chartvalues = []; var chartlabels = [];  //console.info("chartvalues:"+chartvalues); //return "test"; $.blockui({message: '<h1><img src="/img/icons/icon_loading_red.gif" /> please wait - grabbing data...</h1>'});  $.ajax({         url: '/visitdata',         type: 'get',         async: false,         datatype: "json",         success: function (data) {             visitors = data;             console.warn(data);             (var k in visitors){                 if (typeof visitors[k] !== 'function') {                     chartvalues.push(visitors[k].average_order);                 }             }              console.info(chartvalues);             return chartvalues;         }     }); } 

the values being obtained in success function , chartvalues exists before return. no data given original call.

not sure why , need do?