<div onclick="javascript:spoiler('spoiler')">[+/-]</div>
<div id="spoiler" style="display: none">Content</div>
<script>
function spoiler(id)
{
var el = document.getElementByID(id);
if (el) {
el.style.display = el.style.display == 'none' ? '' : 'none';
}
}
</script>