JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://openlayers.org/api/OpenLayers.js"></script>
<div id="map" style="width: 400px; height: 300px;"></div>

<span onclick="foo1()">Click me to unselect bottom left feature with unselect()</span> <br />
<span onclick="foo2()">Click me to unselect all features with unselectAll()</span> <br />

JavaScript

var map, vectorLayer, wmsLayer, selectControl;

window.onload = function() {
    
    map = new OpenLayers.Map('map');
    
    wmsLayer = new OpenLayers.Layer.WMS("OpenLayers WMS",
        "http://vmap0.tiles.osgeo.org/wms/vmap0?",
        {layers: 'basic'},
        {'attribution': 'Provided by OSGeo'}
    );
    
    vectorLayer = new OpenLayers.Layer.Vector('Foo');
    
    map.addLayers([wmsLayer, vectorLayer]);
    map.zoomToMaxExtent();
    
    selectControl = new OpenLayers.Control.SelectFeature(vectorLayer);
    map.addControls([selectControl]);
    selectControl.activate();
    
    vectorLayer.addFeatures(
        [new OpenLayers.Feature.Vector(new OpenLayers.Geometry.Point(10, 10)),
         new OpenLayers.Feature.Vector(new OpenLayers.Geometry.Point(30, 30)),
         new OpenLayers.Feature.Vector(new OpenLayers.Geometry.Point(50, 50))
    ]);    
}

var foo1 = function() { 
    selectControl.unselect(vectorLayer.features[0]);
}
    
var foo2 = function() { 
    selectControl.unselectAll();
}