<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function() {
$('.spoilertext').before('<a class="spoiler" href="#">[spoiler]</a>')
$('.spoiler').click(function(e) {
$(this).next('span').toggle();
e.preventDefault();
return false;
});
});
</script>