$(document).ready(function () {
    SP.SOD.executeFunc('sp.runtime.js', false, function () {
        SP.SOD.executeFunc('sp.js', 'SP.ClientContext', function () {
            SP.SOD.registerSod('sp.taxonomy.js', SP.Utilities.Utility.getLayoutsPageUrl('sp.taxonomy.js'));//loads sp.taxonomy.js file
            SP.SOD.executeFunc('sp.taxonomy.js', false, items);

        });
    });
});

//fetching texonomy terms
function items() {
    var context = SP.ClientContext.get_current();
    var taxSession = SP.Taxonomy.TaxonomySession.getTaxonomySession(context);
    var termStores = taxSession.get_termStores();
    var termStore = termStores.getByName("Managed Metadata Service");
   var termSet = termStore.getTermSet("df2c71c3-17d5-4180-8dd6-b5bf6d0b2cf8");
    var terms = termSet.getAllTerms();
    context.load(terms);
    var name = "";;
    context.executeQueryAsync(function () {
        var termEnumerator = terms.getEnumerator();
        count = 0;
        while (termEnumerator.moveNext()) {
            var oListItemTax = termEnumerator.get_current();
            name = oListItemTax.get_name();
            $('#DropdownList1').append($('<option>', {
                value: name,
                text: name
            }));
            name = "";
        }
    }, function (sender, args) {

        //console.log(args.get_message());
    });
}