last_tab = 'tab1';
	function show(layerName) { 
		document.getElementById(layerName).style.display = '';
		//return 'background-image:url(./images/ltab_blue.gif);';
	} 
	
	function hide(layerName) { 
		document.getElementById(layerName).style.display = 'none';
		//return 'background-image:url(./images/ltab_blue.gif);';
	}	
	function show_next(tab_name) {
		document.getElementById(last_tab).className = 'tab';
		var curr = document.getElementById(tab_name);
		curr.className='tab_hover';
		hide(last_tab+'_data');
		show(tab_name+'_data');
		last_tab=tab_name;
	}
	last_tab2 = 'tab21';
	function show2(layerName) { 
		document.getElementById(layerName).style.display = '';
	} 
	
	function hide2(layerName) { 
		document.getElementById(layerName).style.display = 'none';
	}	
	function show_next2(tab_name) {
		document.getElementById(last_tab2).className = 'tab2';
		var curr = document.getElementById(tab_name);
		curr.className='tab_hover2';
		hide2(last_tab2+'_data');
		show2(tab_name+'_data');
		last_tab2=tab_name;
	}