Giacomo Balli profile picture
Giacomo Balli
Tech Entrepreneur | Advisor | Consultant

I help business owners navigate and leverage technology.

Let's Chat

Email validation

This code sample will allow you to validate an email in real time, as the user types. The email field will have a red border until a valid email is provided.

<input type="email" onkeyup="checkEmail(this)" placeholder="Your email" />

function checkEmail(el) {
    var val = el.value;
    var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    if (!re.test(val)) {"2px solid red";
        return false;
    return true;

- add the onkeyup event handler

This snippet focuses on iOS development. Make sure to verify/adapt any vendor prefixes. Back to main listing.

Published: Mon, 11 Jan 2016 19:52:52 +0000