JSFiddle - React, Tailwind, and code Playground
HTML
<div class="form-group">
<label for="senha" class="required">Senha</label>
<input type="text" class="form-control" id="senha" name="senha" value="" autocomplete="off" data-toggle="popover" data-trigger="hover" data-placement="top" data-content="" />
</div>
<div id="teste"></div>
JavaScript
$("#senha").on("keyup", function(){
if( $(this).val() === $(this).val().toUpperCase() ){
var qtdMaiuscula = parseInt( $(this).val().length );
}
$('#teste').html( qtdMaiuscula );
});