Trigger click event from a div element on an OpenLayers Map

I want to create an animation on a cluster on an OpenLayers Map. This animation is triggered by clicking a button on a div HTML Sidebar. The animation works when I click directly on the cluster, but it does not work when I click the button.

Example of the Maps:

How do I connect the button to the cluster?

Part of the Code:

function markerClick(mKey) {

  var smallCircle = new ol.style.Circle({
    radius: 5,
    stroke: new ol.style.Stroke({
      color: "rgba(0,255,255,1)",
      width: 1
    }),
    fill: new ol.style.Fill({
      color: "rgba(0,255,255,0.3)"
    })
  });

  var style1 = new ol.style.Style({
    image: smallCircle,

    // Draw a link beetween points (or not)
    stroke: new ol.style.Stroke({
      color: "#fff",
      width: 1
    })
  });

  var selectCluster = new ol.interaction.SelectCluster({
    // Point radius: to calculate distance between the features
    pointRadius: 35,
    animate: true,
    // Feature style when it springs apart
    featureStyle: function() {
      return [style1]
    },
    //selectCluster: false, // disable cluster selection
    // Style to draw cluster when selected
    /*style: function(f,res)
    {

    }*/
  });
  window.cluster_click = selectCluster;
  map.addInteraction(selectCluster); //new

  //Test
  selectCluster.getFeatures().on(['add'], function(e) {
    //another function here
    debugger;
  })
}

The function is supposed to enter the selectCluster.getFeatures().on(['add'], function (e) but it does not.

How do I connect this button/link from a div html element to the OpenLayers' layer?