JSFiddle - React, Tailwind, and code Playground

by David Storey

HTML

<p id="support">Is performance.now supported?</p>

CSS

.supported {
    background-color: lime;
}
.unsupported {
    background-color: red;
}
.prefixed {
 background-color: orange;
}   
}

JavaScript

var el = document.getElementById("support");

if (window.performance && typeof window.performance.now !== "undefined") {
    el.textContent = "performance.now is supported!";
    el.className = "supported";
} else if (window.performance && typeof window.performance.webkitNow !== "undefined") {
    el.textContent = "performance.webkitNow is supported!";
    el.className = "prefixed";
} else {
    el.textContent = "performance.now is not supported :(";
    el.className = "unsupported";
}