function gui_toggle(caller_id)
{
	caller = document.getElementById(caller_id);
	
	
	if(caller == null) {
	 return false;	
	}
	
	if(caller.style.display == 'none') {		
		caller.style.display = 'block';
		
	} else {
		caller.style.display = 'none';
	}
	
	return true;
}


function display(obj){
	//alert(obj.href);
	document.getElementById('main_image').src = obj.href;
}