JSFiddle - React, Tailwind, and code Playground

HTML

Click me

JavaScript

document.onclick=function() {

    var popup = open("about:blank", 'bob');
    setTimeout(function() {
        // let the popup load (no load event)
        popup.document.body.innerHTML = '<p>Hello World</p>';
        var elem = $('p', popup.document);
        var text;
        try {
            text = "width = " + elem.width();
        } catch (e) {
            text = e.toString();
        }
        popup.close();
        alert(text);
    }, 100);

}