function insert_html() {
	let elements = document.getElementsByClassName("insert_html");
	for (let element of elements) {
		let path = (element.dataset.path);
		fetch(path)
			.then(response => response.text())
			.then(data => element.innerHTML = data)
			.catch(error => console.log('Error:', error));
		element.classList.replace("insert_html", "inserted_html");
	};
}

// create an observer on everytime some HTML is loaded on the whole page (heavy solution...)
const callback = (mutation_list, observer) => insert_html();
const observer = new MutationObserver(callback);
const targetNode = document.body;
const config = { attributes: true, childList: true, subtree: true };
// Start observing the target node for configured mutations
observer.observe(targetNode, config);