var navUnit = new Array("coronal", "spinal", "mriaxial", "mricoronal", "mrisagittal");

// list of button images

coronalOff = new Image(436,30); 
coronalOff.src = "images/coronalOff.gif";
spinalOff = new Image(436,36); 
spinalOff.src = "images/spinalOff.gif";
mriaxialOff = new Image(436,32); 
mriaxialOff.src = "images/mriaxialOff.gif";
mricoronalOff = new Image(436,37); 
mricoronalOff.src = "images/mricoronalOff.gif";
mrisagittalOff = new Image(436,34); 
mrisagittalOff.src = "images/mrisagittalOff.gif";
kwOff = new Image(141,24); 
kwOff.src = "images/kwOff.gif";
ehslOff = new Image(268,24); 
ehslOff.src = "images/ehslOff.gif";
uuOff = new Image(134,24); 
uuOff.src = "images/uuOff.gif";

coronalOn = new Image(436,30); 
coronalOn.src = "images/coronalOn.gif";
spinalOn = new Image(436,36); 
spinalOn.src = "images/spinalOn.gif";
mriaxialOn = new Image(436,32); 
mriaxialOn.src = "images/mriaxialOn.gif";
mricoronalOn = new Image(436,37); 
mricoronalOn.src = "images/mricoronalOn.gif";
mrisagittalOn = new Image(436,34); 
mrisagittalOn.src = "images/mrisagittalOn.gif";
kwOn = new Image(141,24); 
kwOn.src = "images/kwOn.gif";
ehslOn = new Image(268,24); 
ehslOn.src = "images/ehslOn.gif";
uuOn = new Image(134,24); 
uuOn.src = "images/uuOn.gif";

function layerUp(layerName){
	
		for (i=0; i<navUnit.length; i++)
		{
		eval("document." + navUnit[i] + ".src = " + navUnit[i] +"Off.src");
		}
		eval("document." + layerName + ".src = " + layerName + "On.src");
		
		//put browser detection in here 
//one for pre 4.0 another for document.layers and else for the script below
	if (document.layers){
		for (i=0; i<navUnit.length; i++)
		{
		hideName = navUnit[i] + "Copy";
		document.layers[hideName].visibility = "hidden";
		}
		layerName = layerName + "Copy";
		document.layers[layerName].visibility = "visible";
		}
	else if(document.all){
// this one is for IE 4 (i think)
		for (i=0; i<navUnit.length; i++)
		{
		hideName = navUnit[i] + "Copy";
		document.all[hideName].style.visibility = "hidden";
		}
		layerName = layerName + "Copy";
		document.all[layerName].style.visibility = "visible";
		}
	else{
//this is the IE5 NS6 layer script
		for (i=0; i<navUnit.length; i++){
		var hideCopy = navUnit[i] + "Copy"
		document.getElementById(hideCopy).style.visibility="hidden";
		}
		layerName = layerName + "Copy";
		document.getElementById(layerName).style.visibility="visible";
		}
	}