ajax autocomplete populated

I have an autocomplete ajax script (see below) how do I populate the list from a recordset?

 <script>
        $(function() {
        var availableTags = [
        "435451", "430002", "3430003", "6760004", "73405","56766"  <-- must populate this list dynamically  from  database  there are 900 rows and added each day bThis list cannot be static it must be dynamic only.
 ];
        $( "#itemID" ).autocomplete({
        source: availableTags
        });
        });
 </script>