function change_class(trigger,target) {
	var n01=document.getElementById('n01').getElementsByTagName('a')[0];
	var n02=document.getElementById('n02').getElementsByTagName('a')[0];
	var n03=document.getElementById('n03').getElementsByTagName('a')[0];
	var n01_2=document.getElementById('n01_2');
	var n02_3=document.getElementById('n02_3');
	
	var target=document.getElementById(target);
	
	if (trigger==n01) {
		if (target.className=='hover02') target.className='hover00';
		else target.className='hover02';
	}
	
	if (trigger==n02 && target==n01_2) {
		if (target.className=='hover01') target.className='hover00';
		else target.className='hover01';
	}
	
	if (trigger==n02 && target==n02_3) {
		if (target.className=='hover02') target.className='hover00';
		else target.className='hover02';
	}
	
	if (trigger==n03) {
		if (target.className=='hover01') target.className='hover00';
		else target.className='hover01';
	}
}