detectie.js

function isIEBrowser() {
    const userAgent = window.navigator.userAgent;

    if (userAgent.includes("MSIE") || userAgent.includes("Trident"))
        return true;

    return false;
}

document.addEventListener('DOMContentLoaded', function(e) {
    const isInternetExplorer = isIEBrowser();
    if (isInternetExplorer) {
        console.warn("Internet Explorer browser detected !");
        // Do something about it...
    }
});