dropdown values bind dynamically using jquery

var arrData=[];     //  arrData can be array or key value pair 
arrData.push({Key:1, value:val1});
arrData.push({Key:2, value:val2});

var options=FormatDDL (arrData);
 $('#ddlAgent').append(options);

function  FormatDDL (data) {
       var options;
       options += '<option value="-Select-">-Select-</option>';
       $.each(data, function (i) {
         options += '<option value="' + data[i].Key + '">' + data[i].Value + '</option>';
       });
       return options;
   }