var last_tab;
function TabShow(layerName) {
	document.getElementById(layerName).style.display = '';
}
function TabHide(layerName) {
	document.getElementById(layerName).style.display = 'none';
}
function TabSelect(tab_name) {
	var curr = document.getElementById(tab_name);
	curr.className='selected';
	if(tab_name != last_tab) {
		if(last_tab != undefined) {
			document.getElementById(last_tab).className = '';
			TabHide(last_tab+'_data');
		}
		TabShow(tab_name+'_data');
		last_tab=tab_name;
	}
}