function set_tabs () {
	var loc = location.href;
//	alert(loc.substring(0,43));
	if (loc.substring(0,42) == 'http://www.icpsr.umich.edu/ICSC/exercises/')
	{
		var tab = document.getElementById('t04');
		tab.id = 'current';
	}
	else if (loc.substring(0,45) == 'http://www.icpsr.umich.edu/ICSC/datasets.html')
	{
		var tab = document.getElementById('t03');
		tab.id = 'current';
	}
	else if (loc.substring(0,47) == 'http://www.icpsr.umich.edu/ICSC/background.html')
	{
		var tab = document.getElementById('t02');
		tab.id = 'current';
	}
	else if (loc.substring(0,42) == 'http://www.icpsr.umich.edu/ICSC/about.html')
	{
		var tab = document.getElementById('t01');
		tab.id = 'current';
	}
	else if (loc.substring(0,45) == 'http://www.icpsr.umich.edu/ICSC/overview.html')
	{
		var tab = document.getElementById('t05');
		tab.id = 'current';
	}
	else
	{
		var tab = document.getElementById('t00');
		tab.id = 'current';	
	}

}