var button_name = new Array();
	button_name[0] = '6R';
	button_name[1] = '12R';
	button_name[2] = '26A';
	button_name[3] = '6R73';
	button_name[4] = '12R49';
	button_name[5] = '26A38';

// preload and turnon/off images

	pic6Rtlbtn_on = new Image(171,23);
	pic6Rtlbtn_on.src = "img/tlbtn_6Rmo.png";
	pic6Rtlbtn_off = new Image(171,23);
	pic6Rtlbtn_off.src = "img/tlbtn_6R.png";
	pic12Rtlbtn_on = new Image(171,23);
	pic12Rtlbtn_on.src = "img/tlbtn_12Rmo.png";
	pic12Rtlbtn_off = new Image(171,23);
	pic12Rtlbtn_off.src = "img/tlbtn_12R.png";
	pic26Atlbtn_on = new Image(171,23);
	pic26Atlbtn_on.src = "img/tlbtn_26Amo.png";
	pic26Atlbtn_off = new Image(171,23);
	pic26Atlbtn_off.src = "img/tlbtn_26A.png";

	pic6R73tlbtn_on = new Image(171,26);
	pic6R73tlbtn_on.src = "img/tlbtn_6R73mo.png";
	pic6R73tlbtn_off = new Image(171,26);
	pic6R73tlbtn_off.src = "img/tlbtn_6R73.png";
	pic12R49tlbtn_on = new Image(171,26);
	pic12R49tlbtn_on.src = "img/tlbtn_12R49mo.png";
	pic12R49tlbtn_off = new Image(171,26);
	pic12R49tlbtn_off.src = "img/tlbtn_12R49.png";
	pic26A38tlbtn_on = new Image(171,26);
	pic26A38tlbtn_on.src = "img/tlbtn_26A38mo.png";
	pic26A38tlbtn_off = new Image(171,26);
	pic26A38tlbtn_off.src = "img/tlbtn_26A38.png";

function turnontl(place,imgName) {
      document[place].src= eval(imgName + "_on.src"); 
}

function turnofftl(place,imgName) {
      document[place].src= eval(imgName + "_off.src"); 
}


// assign button displays

	var timeline_regions = new Array();
	timeline_regions[0] = '6regions.html';
	timeline_regions[1] = '12regions.html';
	timeline_regions[2] = '26areas.html';
	timeline_regions[3] = '6regions.html';
	timeline_regions[4] = '12regions.html';
	timeline_regions[5] = '26areas.html';

	function displayregionbutton(btnNo) {
		document.write('<a href="'+timeline_regions[btnNo]+'" onmouseover="turnontl(\'tl'+button_name[btnNo]+'\',\'pic'+button_name[btnNo]+'tlbtn\')" onmouseout="turnofftl(\'tl'+button_name[btnNo]+'\',\'pic'+button_name[btnNo]+'tlbtn\')"><img src="img/tlbtn_'+button_name[btnNo]+'.png" name="tl'+button_name[btnNo]+'" border="0"></a>');
}