JSFiddle - React, Tailwind, and code Playground
HTML
<input id="mytextbox">
JavaScript
$('#mytextbox').bind('keyup blur',function() {
$(this).val($(this).val().replace(/[^A-Za-z]/g,''))
});
<input id="mytextbox">
$('#mytextbox').bind('keyup blur',function() {
$(this).val($(this).val().replace(/[^A-Za-z]/g,''))
});