function MACKAY_all_off() {		
	MACKAY_layerVisibility('navlayer1', 'hidden');		
	MACKAY_layerVisibility('navlayer2', 'hidden');				
	MACKAY_layerVisibility('navlayer3', 'hidden');		
	MACKAY_layerVisibility('navlayer4', 'hidden');		
	MACKAY_layerVisibility('navlayer5', 'hidden');		
	MACKAY_layerVisibility('navofflayer','hidden');
}
	
function MACKAY_Secondary(secondary) {
	MACKAY_layerVisibility('navofflayer', 'visible');
	MACKAY_layerVisibility(secondary, 'visible');
}

// Call this to change the visibility of a layer
function MACKAY_layerVisibility() { 
 for (var i=0; i<MACKAY_layerVisibility.arguments.length; i+=2) {
 if (document.getElementById) { 
 document.getElementById(MACKAY_layerVisibility.arguments[i]).style.visibility=MACKAY_layerVisibility.arguments[i+1];
 } else {
 eval(parentdoc+MACKAY_layerVisibility.arguments[i]+parentsty).visibility = MACKAY_layerVisibility.arguments[i+1];
 }
 }
}

function emailCheck(emailStr)
 {
 var emailPat=/^(.+)@(.+)$/
 var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
 var validChars="\[^\\s" + specialChars + "\]"
 var quotedUser="(\"[^\"]*\")"
 var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
 var atom=validChars + '+'
 var word="(" + atom + "|" + quotedUser + ")"
 var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
 var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
 var matchArray=emailStr.match(emailPat)

 if (matchArray==null)
 {
	alert("The email address does not seem to be valid (check \"@\"and \".\" characters).")
	return true
 }
 var user=matchArray[1]
 var domain=matchArray[2]

 if (user.match(userPat)==null)
 {
 alert("The email address does not seem to be valid (check \"@\"and \".\" characters).")
 return true
 }

 var IPArray=domain.match(ipDomainPat)
 if (IPArray!=null)
 {
	 for (var i=1;i<=4;i++) {
	 if (IPArray[i]>255) {
	  alert("The email address destination IP address does not seem to be valid.")
		return true
	 }
 }
 return false
}

var domainArray=domain.match(domainPat)
if (domainArray==null) {
	alert("The email address does not seem to be valid (check \"@\"and \".\" characters).")
 return true
}

var atomPat=new RegExp(atom,"g")
var domArr=domain.match(atomPat)
var len=domArr.length
if (domArr[domArr.length-1].length<2 || 
 domArr[domArr.length-1].length>3) {
 // the address must end in a two letter or three letter word.
 alert("The email address must end in a three-letter domain, or a two-letter country code.")
 return true
}

if (len<2) {
 var errStr="The email address is missing a hostname."
 alert(errStr)
 return true
}

return false;
}