JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="key" />
CSS
.error{border:1px solid #F00;}
JavaScript
$('#key').on('keydown',function(e){
var deleteKeyCode = 8;
var backspaceKeyCode = 46;
if ((e.which>=48 && e.which<=57) || (e.which>=96 && e.which<=105) || e.which === deleteKeyCode || e.which === backspaceKeyCode)
{
$(this).removeClass('error');
return true;
}
else
{
$(this).addClass('error');
return false;
}
});