var myrules = {
	'.research-interest' : function(interest){
		interest.onclick = function(){
			showElements(interest.id);
		};
	}
};

Behaviour.register(myrules);

function showElements(id) {

  var topic = $('topic');
  var source = $(id);
  topic.textContent = source.textContent;

  var allElements = $$('div.faculty-summary');
  if (id=='all-interests') {
	for(var i=0; i<allElements.length; i++){
		allElements[i].style.display='block';
	}    	
	return;
  }
  var selectedElements = $$('div.' + id);
	for(var i=0; i<allElements.length; i++){
		allElements[i].style.display='none';
	}
	for(var i=0; i<selectedElements.length; i++){
		selectedElements[i].style.display='block';
	}
}