function showSub(subNum) {
		var i=0;
		while(myElem = eval("document.getElementById('sub_"+i+"');")) {
			if(i==mainNum){
		 		myElem.style.display = '';
			}
			else {
		 		myElem.style.display = 'none';
			}
			i++;
		}
}

function showLayer(showMe) {
	var i=1;
	while(myElem = eval("document.getElementById('sub_"+i+"');")) {
	
		if(i==showMe){
		 myElem.style.display = '';
		}
		else {
		 myElem.style.display = 'none';
		}
		i++;
	}
}