oss使用js的sdk，报错

<script type="text/javascript">
      var client = new OSS.Wrapper({
               region: 'oss-cn-shenzhen.aliyuncs',
               secure: true,    
              accessKeyId: '',
              accessKeySecret: '',
              bucket: ''
    });



      document.getElementById('selectfiles').addEventListener('change', function (e) {
              var file = e.target.files[0];
              var storeAs = '12.jpg';

              alert(storeAs);

              client.multipartUpload(storeAs, file).then(function (result) {
                    alert('sucess');
                  alert(result);
              }).catch(function (err) {
                    alert('error');
                   alert(err);
              });
           });
</script>