<div id="chart"></div>
<script>
$("#chart").kendoChart({
  series: [{
    type: "line",
    name: "Series A",
    data: [1, 2, 3],
    legendItem: {
      highlight: {
        visible: true,
        markers: {
          background: "red"
        }
      }
    }
  }]
});
</script>