function showTab (myObj,that)
{
	actualTab = myObj;
	
	if(actualTab != oldTab)
	{
		
		document.getElementById(oldTab).style.display = 'none';
		document.getElementById(actualTab).style.display = 'block';
		
		
		//Neuen Tab Aktivklasse zuweisen
		links = document.getElementById('tnav').getElementsByTagName('span');
	
		for(e=0;e<links.length;e++)
		{
			links[e].className = "";
		}
		that.className = "active";
		
		oldTab = actualTab;
		
	}
	
}