[Decode]

<style>
	.hidden {
		display: none;
	}
</style>

<div>
	<button onclick="toggle(this.nextElementSibling)">Toggle</button>
	<span class="hidden"><span style="color: red;">Вася</span> лох!</span>
</div>

<div>
	<button onclick="toggle(this.nextElementSibling)">Toggle</button>
	<span class="hidden"><span style="color: red;">Петя</span> лох!</span>
</div>


<script>
	function toggle(elem) {
		elem.style.display = (elem.offsetHeight) ? '' : 'block';
	}
</script>