var getJSON = function(url) {
 return new Promise(function(resolve, reject) {
   var xhr = new XMLHttpRequest();
   xhr.open('get', url, true);
   xhr.responseType = 'json';
   xhr.onload = function() {
     var status = xhr.status;
     if (status == 200) {
       resolve(xhr.response);
     } else {
       reject(status);
     }
   };
   xhr.send();
 });
};

setInterval(function() {
getJSON('http://www.lazada.com.my/ajax/lottery/spinTheWheel/?lang=en&platform=desktop&wheelToken=b5dd7e9dcbde84b3e11a9ae90d377b02&dpr=2').then(function(data) {
   if(data.data.voucherCode) {
   console.log('Voucher: ' + data.data.voucherCode);
   }
   else { console.log('no voucher'); }
   }, function(status) { //error detection....
 alert('Something went wrong.');
}); }, 5000);