Botão de mostrar e olcutar

Abaixo o Codigo o Resto e apenas editar ele.

<div class="pre-spoiler"> <input id="xs" value="Mostrar" style="margin-left: 50px; padding: 0px; width: 70px; " onclick="if (this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display != '') { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = '';this.innerText = ''; this.value = 'Ocultar'; } else { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'none'; this.value = 'Mostrar';}" type="button"> </div> <div> <div class="spoiler" style="display: none;"> Conteudo mostrar/ocultar </div></div>

e só gente até outra!!