JavaScript global not keeping scope? creating an autocomplete webservice json object

Question

Hi I am trying to autocomplete a list of cities, but the json object returned is not formatted for use in autocomplete that requires a field called "label":"cityname" to display the autocomplete, so i am trying to reformat the json object using an ajax call and writting it to a global variable, the issue is that once the ajax call returns, my jsData is [] an empty array... What am I doing wrong? and why doesn't the global variable keep a value?

http://www.andymatthews.net/read/2012/03/27/jQuery-Mobile-Autocomplete-now-available

<script>
        $("#nec").bind("pageshow", function(e) {
            var jsData = [];

            $.ajax({
                   url: "http://localhost:8084/REST/resources/cities",
                   data:{},
                   type: 'GET',
                   crossDomain: true,
                   dataType: 'jsonp',
                   jsonp: 'jsonp',
                   jsonpCallback: 'jsoncallback',
                   error: function(error){
                       console.log(error);
                   },
                   success: function(result) {
                       for (i = 0; i < result.length; i++){
                             jsData.push({label:result[i].name, value:result[i]}); 
                        }
                        console.log(JSON.stringify(jsData));   
                       },
                });

            $("#textinput").autocomplete({
                target: $('#suggestions'),
                source: jsData,
                minLength: 1
            });

});
    </script>

I am a little fresh on the JS front, so there are a few things that I still have not got a hang of

Answer 1

You have to put

 $("#textinput").autocomplete({
     target: $('#suggestions'),
     source: jsData,
     minLength: 1
 });

within your success() function.

Because, jsData becomes update within success() . Execution of pageshow event's anonymous function is faster than execution of success() . So, within that function jsData remain empty.

You can retrieve data through autocomplete itself. See here

Answer 2

The problem is that jsData isn't global, but scoped inside the anonymous function.

    var jsData = [];   // make that here.

    $("#nec").bind("pageshow", function(e) {

        $.ajax({
               url: "http://localhost:8084/REST/resources/cities",
               data:{},
               type: 'GET',
               crossDomain: true,
               dataType: 'jsonp',
               jsonp: 'jsonp',
               jsonpCallback: 'jsoncallback',
               error: function(error){
                   console.log(error);
               },
               success: function(result) {
                   for (i = 0; i < result.length; i++){
                         jsData.push({label:result[i].name, value:result[i]}); 
                    }
                    console.log(JSON.stringify(jsData));   
                   },
            });

        $("#textinput").autocomplete({
            target: $('#suggestions'),
            source: jsData,
            minLength: 1
        });

Although, i wouldn't advise a global variable. But, if it works for you, it's your wish.