.imageoverlay { 
   position: relative; 
   width: 100%; /* for IE 6 */
}
 

.onsale-section {
  position: absolute;
  top: -6px;
  right: 5px;
}

.onsale-section:after {
  position: absolute;
  content: '';
  display: block;
  width: 0;
  height: 0;
  border-left: 27px solid transparent;
  border-right: 27px solid transparent;
  border-top: 6px solid #3bac53;
}

.onsale {
  position: relative;
  display: inline-block;
  text-align: center;
  color: #fff;
  background: #3bac53;
  font-size: 10px;
  line-height: 1;
  padding: 12px 8px 6px;
  border-top-right-radius: 8px;
  width: 58px;
  text-transform: uppercase
}

.onsale:before,
.onsale:after {
  position: absolute;
  content: '';
  display: block;
}

.onsale:before {
  background: #3bac53;
  height: 7px;
  width: 6px;
  left: -6px;
  top: 0;
}

.onsale:after {
  background: #3bac53;
  height: 7px;
  width: 8px;
  border-radius: 8px 8px 0 0;
  left: -8px;
  top: 0;
}