function change(id, tova) {
	var copy;
	var last;
	var elements;
	var elements = new Array();
	
	if (tova != null ){	
	    for(i=1; i<=3; i++) {
		    elements[i] = document.getElementById('b'+i);
	    }
	    //alert('id'+id);
	    for(i=1; i<=3; i++) {
    	    
		    if(i == id) {
		    //alert('i'+i);
			    elements[id].style.display = 'block';
			    //elements[id].style.visiblility = 'visible';
		    } else {
			    elements[i].style.display = 'none';
			    //elements[i].style.visiblility = 'hidden';
		    }
	    }
	    elements = new Array();
	    elements = document.getElementById('main_a').getElementsByTagName('li');
	    last = elements[2];	
	    copy = last.innerHTML;
	    //alert('copy'+copy);
	    //alert('tova.parentNode.innerHTML'+tova.parentNode.innerHTML);
	    if (tova.parentNode.innerHTML != copy){
	        last.innerHTML = tova.parentNode.innerHTML;
    	    tova.parentNode.innerHTML = copy;
	    }
    }
}