function changeTab(tabIndex)
{
	var tabIndexes;
	tabIndexes = tabIndex.split('_');
	
	if (tabIndexes)
	{
		var tLen, nTabIndex, onIndex, offIndex, offTabIndex, onTabIndex;
		
		onIndex = tabIndexes[0].concat('_', tabIndexes[1]);
		
		if (tabIndexes[1] == '1')
		{
			offIndex = tabIndexes[0].concat('_', '2');
			offTabIndex1 = offIndex.concat('_on');
			onTabIndex = offIndex.concat('_off');
		}
		else
		{
			offIndex = tabIndexes[0].concat('_', '1');
			offTabIndex1 = offIndex.concat('_on');
			onTabIndex = offIndex.concat('_off');
		}
		
		nTabIndex = tabIndexes[0].concat('_', tabIndexes[1], '_','on');
		
		//change tab
		document.getElementById(tabIndex).style.display='none';
		document.getElementById(nTabIndex).style.display='block';
		document.getElementById(offTabIndex1).style.display='none';
		document.getElementById(onTabIndex).style.display='block';
		
		// change body
		document.getElementById(offIndex).style.display='none';
		document.getElementById(onIndex).style.display='block';
	}
}