lib you linked is a bit crazy, it uses setInterval to guess when a css is properly loaded/applied and delays running dependent code imho this is sufficient:

lib you linked is a bit crazy, it uses setInterval to guess when a css is properly loaded/applied and delays running dependent code imho this is sufficient: define('css', function () { return { load: function (name, parentRequire, onload, config) { console.log('loading css ' + name); const link = document.createElement('link'); link.type = 'text/css'; link.rel = 'stylesheet'; link.href = name + '.css'; document.getElementsByTagName('head')[0].appendChild(link); setTimeout(onload, 0); } }; }); usage: require(['lib/js/jquery-ui.min', 'css!lib/css/jquery-ui.min'], function () { // jquery-ui magic goes here });