javascript css head
var head = document.getElementsByTagName('head')[0];
var css = [
'https://unpkg.com/[email protected]/dist/leaflet.css',
'https://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/1.4.1/MarkerCluster.css',
'https://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/1.4.1/MarkerCluster.Default.css'
];
css.forEach(function (item) {
var link = document.createElement('link');
link.rel = 'stylesheet';
link.type = 'text/css';
link.href = item;
head.appendChild(link);
});