function downloadJSAtOnload() {
var element = document.createElement("script");
element.src = "/wp-content/plugins/add-custom-google-tag-manager/assets/js/loader.js";
document.body.appendChild(element);
}
if (window.addEventListener)
window.addEventListener("load", downloadJSAtOnload, false);
else if (window.attachEvent)
window.attachEvent("onload", downloadJSAtOnload);
else window.onload = downloadJSAtOnload;