<script>
function my_f(objName) {
var object = document.getElementById(objName);
object.style.display == 'none' ? object.style.display = 'block' : object.style.display = 'none'
}
</script>
<a href="javascript:void(0)" onclick="my_f('textid')">(+)</a>
<div id="textid" style="display:block;">
скрытый текст
</div>