function getJSON(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();
    });
};