Several rudamentary samples for obtaining bits of information for a Select2 dropdown using AJAX and GIS

AnotherSample_Select2_and_GIS_Pull.js

$("#parcelByAddress.select2").select2({
    placeholder: "Select...",
    minimumInputLength: 2,
    allowClear: true,
    autoClear: false,
    //initSelection: function (element, callback) {
    //    var elementText = element.val();
    //    data = { id: elementText, text: elementText };
    //    callback(data);
    //},
    ajax: {
        quietMillis: 100, /* Your URL will difer */
        url: 'http://gisdata.<YourServer>.net/public/rest/services/A_POL_Basemap/MapServer/33/query?geometryType=esriGeometryEnvelope&spatialRel=' + 
              'esriSpatialRelIntersects&relationParam=&outFields=ADDRESS%2CMAP_PARCEL%2COWNER&returnGeometry=false&returnIdsOnly=' +
              'false&returnCountOnly=false&orderByFields=ADDRESS&returnZ=false&returnM=false&f=pjson',
        dataType: 'jsonp', /*JSONP required to prevent XMLHttpRequest cannot load "No 'Access-Control-Allow-Origin' error */
        data: function (term) {
            term = "" + term;
            return 'where=ADDRESS+LIKE+%27%25' + term.toUpperCase() + '%25%27' +
                        '+OR+OWNER+LIKE+%27%25' + term.toUpperCase() + '%25%27' +
                        '+OR+MAP_PARCEL+LIKE+%27%25' + term + '%25%27 ' +
                        '+OR+CONCAT(ADDRESS,OWNER)+LIKE+%27%25' + term.toUpperCase().replace(' ', '%25') + '%25%27 '
        },
        results: function (data) {
            var lastStreet = '';
            var newJson = { data: [] };
            return { results: $.map(data.features, function (item) {
                
                var fullStreetName = "";
                
                if (item.attributes.ADDRESS !== null) { fullStreetName += item.attributes.ADDRESS; }
                if (item.attributes.MAP_PARCEL !== null) { fullStreetName += " [PARCEL: " + item.attributes.MAP_PARCEL + "]"; }
                if (item.attributes.OWNER !== null) { fullStreetName += " (" + item.attributes.OWNER + ")"; }

                if (fullStreetName != lastStreet) {
                    lastStreet = fullStreetName;
                    //newJson.data.push(
                    return {
                        id: item.attributes.MAP_PARCEL,
                        text: fullStreetName,
                    };
                }
            })};
        }
    }
});



$("#GetZipDistrict").click(function () {
    $("#GetZipDistrictLabel").attr("hidden", "hidden");
    $.ajax({
        url: 'http://gisdata.<YourServer>.net/public/rest/services/CompositeAddressLocatorWGS84/GeocodeServer/'  +
             'findAddressCandidates?SingleLine=&outFields=ZIP&outSR=&searchExtent=&f=pjson&Street=' + $("#StreetNumber").val() + 
             '+' + $("#GisStreetName").val().replace(" ", "+") + '&City=<YourCity>&State=&ZIP=',
        dataType: 'jsonp',
        success: function (data) {
            //PARSE ZIP OUT OF RETURNED JSONP
			var returnedData = data.candidates[0]; //retreive the first (highest percentage) result
			var geocodeLocation;

            if (data.candidates.length > 0) {

				$("input#Zip").val(returnedData.attributes.ZIP);

				//GET GEOCODED LOCATION
				geocodeLocation = returnedData.location.x + "%2C" + returnedData.location.y;

				GetDistrictByGeoCode(geocodeLocation);
			}
			else {
				$("#GetZipDistrictLabel").removeAttr("hidden");
			}
		}
	});
});


function GetDistrictByGeoCode(geocodeLocation) {
    $.ajax({
        url: 'http://gisdata.<YourServer>.net/public/rest/services/Mosquito/Adulticide_Zones/MapServer/0/query?where=&text=&objectIds=&time=&geometry=' +
                geocodeLocation + '&geometryType=esriGeometryPoint&inSR=2284&spatialRel=esriSpatialRelIntersects&relationParam=&outFields=DISTRICT&' +
                'returnGeometry=false&maxAllowableOffset=&geometryPrecision=&outSR=&returnIdsOnly=false&returnCountOnly=false&orderByFields=&' +
                'groupByFieldsForStatistics=&outStatistics=&returnZ=false&returnM=false&gdbVersion=&f=pjson',
        dataType: 'jsonp',
        success: function (data) {
            //PARSE ZIP OUT OF RETURNED JSONP
			var returnedData = data.features[0];
			var geocodeLocation;

            if (data.features.length > 0) {
                //SET DISTRICT FIELD
                var district = returnedData.attributes.DISTRICT;
                district = district.toUpperCase();
                
                $("#DistrictId").select2().find("option:contains('" + district + "')").each(function () {
                    $(this).attr("selected", "selected");
                });

				$("#DistrictId").select2().attr("selected", "selected");  //Required for some reason--won't select correctly otherwise.
			}
		}
	});
}