After going through some answers on SO this is my code:
$(".check").keyup(function () {
var VAL = $(this).val();
var email = new RegExp('^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$');
if (email.test(VAL)) {
alert('Great, you entered an E-Mail-address');
}
});
<input type="text" class="check" />
<input type="text" class="check" />
But for some reason it doesn't work.