Teste

<div class="pre-spoiler">
<span style="float: left; padding-top: 2px;">Spoiler</span> <input type="button" onclick="if (this.parentNode.parentNode.getElementsByTagName(' div')[1].getElementsByTagName('div')[0].style.display != '') { this.parentNode.parentNode.getElementsByTagName('d iv')[1].getElementsByTagName('div')[0].style.display = '';this.innerText = ''; this.value = 'Esconder'; } else { this.parentNode.parentNode.getElementsByTagName('d iv')[1].getElementsByTagName('div')[0].style.display = 'none'; this.value = 'Mostrar';}" style="margin: 0px; padding: 0px; width: 80px; font-size: 10px;" value="Esconder"/>
</div>


Gente isso é um teste não liguem