map.js

//var region defined
var region = $('#inputGroupSelect01').val()
region = $('#inputGroupSelect01').change(function() {
  $(this).val()
});

//button click events
$('#load').click(function () {
  //hazardLayer
  var hazardLayer = L.tileLayer.wms("http://localhost:8080/geoserver/tajikistan/wms", {
      layers: `tajikistan:${region}`,
      format: 'image/png',
      transparent: true,
      version: '1.1.0',
      attribution: "country layer"
    });
  hazardLayer.addTo(map);
  $('#clear').click(function () {
  map.removeLayer(hazardLayer);
});
});