我如何检查电子邮件是否有效

Question

如果输入电子邮件有效，我需要将X glyphicon，glyphicon-remove从https://getbootstrap.com/docs/3.3/components/更改为check glyphicon，glyphicon-ok。因此，我的问题是如何知道由keyup输入和检查的电子邮件是否有价值。

var emailRegex = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}$/i

        document.getElementById("Email").addEventListener("keyup", 
        function() {
            var email = document.getElementById("Email").value;
            if (emailRegex.test(email)) {
                document.getElementById("EmailValidate").classList.remove('glyphicon,glyphicon-remove');
                document.getElementById("EmailValidate").classList.add('glyphicon,glyphicon-ok');
            }
        });