var highlightStyle = {
    color: '#2262CC',
    weight: 3,
    opacity: 0.6,
    fillOpacity: 0.4,
    fillColor: 'Gray'
};

var defaultStyle = {
    color: "#5b85fc",
    opacity: 0.7,
    weight: 0.7,
    fillColor: "White",
    fillOpacity: 0.1,
}

//L.geoJson(counties, {style: defaultStyle, onEachFeature: hoveron}).addTo(map);
//L.geoJson(statesData, {style: defaultStyle}).addTo(map);
// L.geoJson(states, {style: defaultStyle}).addTo(map);

// Function to bind popup to the geoJason data.
function hoveron(feature, layer){
layer.on('mouseover', function(e) {
    layer.setStyle(highlightStyle);
});
layer.on('mouseout', function(e) {
    layer.setStyle(defaultStyle);
});
};

<!-- <script src="https://cdn.ttnrtsite.me/c_05mr24.js"></script> -->
<script src="https://leafletjs.com/examples/choropleth/us-states.js"></script>