var navArray = new Array();

navArray[0] = 'navhom';
navArray[1] = 'navabt';
navArray[2] = 'navsrv';
navArray[3] = 'navcrt';
navArray[4] = 'navpto';
navArray[5] = 'navprt';
navArray[6] = 'navcnt';

function opacity(id, opacStart, opacEnd, millisec) {
	//speed for each frame
	var speed = Math.round(millisec / 100);
	var timer = 0;

	//determine the direction for the blending, if start and end are the same nothing happens
	if(opacStart > opacEnd) {
		for(i = opacStart; i >= opacEnd; i--) {
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	} else if(opacStart < opacEnd) {
		for(i = opacStart; i <= opacEnd; i++)
			{
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	}
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
	var object = document.getElementById(id).style; 
	object.opacity = (opacity / 100);
	object.MozOpacity = (opacity / 100);
	object.KhtmlOpacity = (opacity / 100);
	object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
	//if an element is invisible, make it visible, else make it ivisible
	if(document.getElementById(id).style.opacity == 0) {
		opacity(id, 0, 100, millisec);
	} else {
		opacity(id, 100, 0, millisec);
	}
}

function blendimage(divid, imageid, imagefile, millisec) {
	var speed = Math.round(millisec / 100);
	var timer = 0;
	
	//set the current image as background
	document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")";
	
	//make image transparent
	changeOpac(0, imageid);
	
	//make new image
	document.getElementById(imageid).src = imagefile;

	//fade in image
	for(i = 0; i <= 100; i++) {
		setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
		timer++;
	}
}

function currentOpac(id, opacEnd, millisec) {
	//standard opacity is 100
	var currentOpac = 100;
	
	//if the element has an opacity set, get it
	if(document.getElementById(id).style.opacity < 100) {
		currentOpac = document.getElementById(id).style.opacity * 100;
	}

	//call for the function that changes the opacity
	opacity(id, currentOpac, opacEnd, millisec)
}

function swapout(id2)
{ 
	if (whereami.substring(0,3) != 'non')
	{
		currentOpac(whereami,1,150);
		
		if (id2.substring(0,3) != 'non')
		{
			setTimeout("swapVis('" + whereami + "','" + id2 + "')",175);
			setTimeout("currentOpac('" + id2 + "',100, 150)",250);
		}
		else
		{
			setTimeout("document.getElementById('" + whereami + "').style.display = 'none';",175);
		}
	}
	else if (id2.substring(0,3) != 'non')
	{
		document.getElementById(id2).style.display = 'block';
		currentOpac(id2,100,150);
	}
	
	whereami = id2;
}

function swapVis(id1,id2)
{
	document.getElementById(id1).style.display = 'none';
	document.getElementById(id2).style.display = 'block';
}
function swapNav(id,strType)
{
	if (id.id != whereami.substring(3))
	{
		if (strType == 'over')
		{
			id.style.backgroundImage = 'url(images/tab.gif)';
			
			if ((id.id == 'navabt') || (id.id == 'navsrv') || (id.id == 'navcrt') || (id.id == 'navprt'))
			{
				swapout('sub' + id.id);
			}
			else
			{
				swapout('non' + id.id);
			}
		}
		//else
		//{
			//id.style.backgroundImage = null;
			setTimeout("changeout('" + id.id + "')",250);
		//}
	}
}

function changeout(idname)
{
	for (i=0;i<navArray.length;i++)
	{
		if (whereami.substring(3) != navArray[i])
		{
			document.getElementById(navArray[i]).style.backgroundImage = 'none';
		}
	}
}