SOURCE

<div class="corner JDMap_box JDMap_box-orient-vertical JDMap_box-align-center">
 
   <div class="con">测试标注点</div>

</div>

body{
    margin:0;
    padding:0
}
.JDMap_box {
  display: -webkit-box;
  display: -moz-box;
  /*display: box;*/
}

.JDMap_box-orient-vertical {
  /* autoprefixer: ignore next */
  -webkit-box-orient: vertical;
  -moz-box-orient: vertical;
}

.JDMap_box-flex-1 {
  -webkit-box-flex: 1;
  -moz-box-flex: 1
}

.JDMap_box-flex-2 {
  -webkit-box-flex: 2;
  -moz-box-flex: 2
}

.JDMap_box-align-start {
  -webkit-box-pack: start;
  -webkit-box-align: start;
  -moz-box-pack: start;
  -moz-box-align: start
}

.JDMap_box-align-center {
  -webkit-box-pack: center;
  -webkit-box-align: center;
  -moz-box-pack: center;
  -moz-box-align: center
}

.JDMap_box-align-end {
  -webkit-box-pack: end;
  -webkit-box-align: end;
  -moz-box-pack: end;
  -moz-box-align: end
}
.corner{
    width: 0px;
    height: 0px;
    border-top: 6px solid rgba(18, 18, 157,100);
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    position: absolute;
    pointer-events: none;
    left:200px;
    top:100px;
}

.con{
    background-color:rgb(18, 18, 157);
    color:#fff;
    position: absolute;
    bottom:6px;
    white-space:nowrap;
}