function ChangeLayer(type)
{
	var l1 = document.getElementById('laying_1');
	var l2 = document.getElementById('laying_2');
	var l3 = document.getElementById('laying_3');
	var t1 = document.getElementById('text_1');
	var t2 = document.getElementById('text_2');
	var t3 = document.getElementById('text_3');
	if (l1 != null && l2 != null && l3 != null && t1 != null && t2 != null && t3 != null)
	{
	switch (type)
	{
		case '1':
			if (l2.className != 'select')
			{
				l2.className = 'select';
				t2.style.display = '';
		    	l1.className = l3.className = 'deselect';
		    	t1.style.display = t3.style.display = 'none';
		    }
			break;
		case '2':
			if (l3.className != 'select')
			{
		    	l3.className = 'select';
		    	t3.style.display = '';
		    	l2.className = l1.className = 'deselect';
		    	t2.style.display = t1.style.display = 'none';
		   	}
			break;
		default:
			if (l1.className != 'select')
			{
			    l1.className = 'select';
			    t1.style.display = '';
			    l2.className = l3.className = 'deselect';
			    t2.style.display = t3.style.display = 'none';
		    }
			break;
		}
	}
}