Boton mostrar o ocultar texto o codigos.

codigo html:

<div class="pre-spoiler"> <span style="color: #00ffff;">AQUI COLOCAN EL TEXTO QUE SE VERA AL DAR CLIC</span> <input type="button" value="Mostrar" style="width:80px;font-size:10px;margin:0px;padding:0px;" 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';}" /><br /> </div> <br /> <div> <div class="spoiler" style="display: none;"> AQUI ESCRIBEN TODO EL CONTENIDO QUE OCULTARAN YA SEA UN CHAT, REPRODUCTOR,ETC<br /> </div> </div>