JS workflow
HTML
<div id="output"></div>
JavaScript
const output = document.querySelector('#output');
[...Array(4)].forEach((_, i) => {
const iframe = document.createElement('iframe');
iframe.name = i;
iframe.width = 1;
iframe.height = 1;
iframe.src = i % 2 ? 'http://localhost:8080/' : 'http://127.0.0.1:8090/';
output.appendChild(iframe);
});