JSFiddle - React, Tailwind, and code Playground
HTML
<input class="onealphaonly">
JavaScript
$('.onealphaonly').bind('keyup blur',function(){
var node = $(this);
node.val(node.val().replace(/[^a-zA-Z]/g{1},'') ); }
);
<input class="onealphaonly">
$('.onealphaonly').bind('keyup blur',function(){
var node = $(this);
node.val(node.val().replace(/[^a-zA-Z]/g{1},'') ); }
);