https://omnetpp.org/js/copyToClipboard.js

1
2document.addEventListener('DOMContentLoaded', function() {
3    var buttons = document.querySelectorAll('.copy-button');
4    buttons.forEach(function(button) {
5        button.addEventListener('click', function() {
6            var content = this.parentElement.querySelector('.content').innerText;
7            var elem = document.createElement("textarea");
8            document.body.appendChild(elem);
9            elem.value = content;
10            elem.select();
11            document.execCommand("copy");
12            document.body.removeChild(elem);
13        });
14    });
15});