function tabclick(tab)
	{
		switch (tab)
		{
		    case 'tab1':
		        document.getElementById('tab1').style.backgroundImage = 'url(images/light_bg_tab.gif)';
				document.getElementById('tab2').style.backgroundImage = 'url(images/dark_bg_tab.jpg)';
				document.getElementById('d1').style. visibility = 'visible';
				document.getElementById('d2').style. visibility = 'hidden';
			break;
			case 'tab2':
		        document.getElementById('tab1').style.backgroundImage = 'url(images/dark_bg_tab.jpg)';
				document.getElementById('tab2').style.backgroundImage = 'url(images/light_bg_tab.gif)';
				document.getElementById('d1').style. visibility = 'hidden';
				document.getElementById('d2').style. visibility = 'visible';
			break;
		}
	}