last_tab = 'tab1';

function show(layerName) {
	document.getElementById(layerName).style.display = '';
}

function hide(layerName) {
	document.getElementById(layerName).style.display = 'none';
}

function show_next(tab_name) {
	document.getElementById(last_tab).className = 'tab';
	var curr = document.getElementById(tab_name);
	//alert("current:"+tab_name);
	//alert("lasttab:"+last_tab);
	curr.className='tab-selected';
	hide(last_tab+'_data');
	show(tab_name+'_data');
	last_tab=tab_name;
}

function show_next_with_landing(tab_name, landing_tab) {
	if(landing_tab != "" && landing_tab != tab_name) {
		last_tab = landing_tab;
	}
	
	document.getElementById(last_tab).className = 'tab';
	var curr = document.getElementById(tab_name);
	curr.className='tab-selected';
	hide(last_tab+'_data');
	//hide(last_tab+'_image');
	
	show(tab_name+'_data');
	//show(tab_name+'_image');
	last_tab=tab_name;
}