jQuery addClass example

Change class name on click in jQuery

by Mohd Zaki

HTML

<input id="firstname" placeholder="first name" onkeyup="lettersOnly(this)">
<input id="lastname" placeholder="last name" onkeyup="lettersOnly(this)">

JavaScript

function lettersOnly(input) {
    var regex = /[^a-z]/gi;
    input.value = input.value.replace(regex, "");
}