var browser = navigator.appName
	var version = parseInt(navigator.appVersion)
	
	var ns5 = (browser == "Netscape" && version > 4)
	var ie4 = (browser == "Microsoft Internet Explorer" && version >= 4)
	var ns3 = (browser == "Netscape" && version == 3)
	var ie3 = (browser == "Microsoft Internet Explorer" && version < 4)
	var ns2 = (browser == "Netscape" && version < 3)
	var ready = false
	
	function init_nav()
	// don't forget to put function call in body tag
{
		if (ie4) block1 = document.getElementById("one").style
		if (ns5) block1 = document.getElementById("one").style
	
		if (ie4) block2 = document.getElementById("two").style
		if (ns5) block2 = document.getElementById("two").style
		
		if (ie4) block3 = document.getElementById("three").style
		if (ns5) block3 = document.getElementById("three").style
		
		ready = true
	}
		
        
	// hide and show for layers
	function showObject(obj) 
	{
		if (ready)
		{
			if (ns5) obj.visibility = "visible"        
			else if (ie4) obj.visibility = "visible"
		}
	}
	
	function hideObject(obj) 
	{
		if (ready)
		{
			if (ns5) obj.visibility = "hidden"        
	        else if (ie4) obj.visibility = "hidden"
		}
	}
	
	function drop(dropnum)
	{
		if (ready)
		{
		//hideall()
			if (dropnum == 1) 
                {
                showObject(block1); 
                }
                
			if (dropnum == 2) 
                {
                showObject(block2); 
                }
                
			if (dropnum == 3) 
                {
                showObject(block3); 
                }
		}
	}
	
	function hideall()
	{
		hideObject(block1);
		hideObject(block2);
		hideObject(block3);
	}
	
	function hideone()
	{
		hideObject(block1);
	}
	
	function hidetwo()
	{
		hideObject(block2);
	}
	
	function hidethree()
	{
		hideObject(block3);
	}
	
	
	function donothing() 
	{}

    
// background change    
    function td_on(tdnumber){
    tdNum = tdnumber
    tdChangeOn = document.getElementById("td" + tdNum +"");
    tdChangeOn.className='on';
    return;
    }       
    
    function td_off(tdnumber){
    tdNum = tdnumber
    tdChangeOff = document.getElementById("td" + tdNum +"");
    tdChangeOff.className='off';
    return;
    }