var behaviourRules = {
	'#logo a img' : function(element){
		element.onmouseover = function(){
			element.src = element.src.replace('.gif', '_over.gif');
			return false;
		}
	},
	'#logo a img' : function(element){
		element.onmouseout = function(){
			element.src = element.src.replace('_over.', '.');
			return false;
		}
	},
	'#menu a img.change' : function(element){
		element.onmouseover = function(){
			element.src = element.src.replace('.gif', '_over.gif');
			return false;
		}
	},
	'#menu a img.change' : function(element){
		element.onmouseout = function(){
			element.src = element.src.replace('_over.', '.');
			return false;
		}
	}}
Behaviour.register(behaviourRules);