// 	JavaScript for www.easterncathedrals.org.uk
//	by Aidann Bowley - www.aidann.co.uk
//	last modified: 29 July 2003
//	-----------------------------------------

//	function checks specifically for browser N4.x or less, 
//	if found to be returns true, else assumes is modern
function n4Check(){
	var appN = navigator.userAgent.toLowerCase();
	var isN4 = false;// default state
			
	//	claims to be Mozilla
	if(appN.indexOf("mozilla") !=-1){
	
		//	 if claims to be version 5+ is Modern
		if(parseInt(appN.substring(11,8)) >=5){
			return isN4;
		}else{//	claims to be version 4.x or less
		
			//	doublecheck the two methods that spoof Mozilla<5 browsers in Modern Browsers (eg IE, opera et al)
			if(appN.indexOf("compatible") !=-1  || ((appN.length-1) != appN.lastIndexOf("\)")) ){
				return isN4;
			}else{//	seems to be N4.x or less
				isN4 = true;
				return isN4;
			}
		}
		
	}
		
}

// function checks jsVersion
// use intro of different objects to js as useful check
function checkJSVersion(){
	if(document.images){
		return 1.1;
	}
}

//	function switches page using best method dependant on Javascript version
function switchPage(mustSwitch,upgradePage){	
	//check minimum jsVersion
	var jsVersion = checkJSVersion();
	if (mustSwitch) {		// if netscape 4 detected, load appropriate alternate page
		if(jsVersion > 1.0) {	// need javascript1.1 to do location.replace
			window.location.replace(upgradePage);// so we don't break the back button
		} else {
			window.location = upgradePage;
		}
	}	
}

//	find out if we need to
var mustSwitch = n4Check();
var upgradePage = "updatebrowser.html";
//	switchpage if browser needs upgrading
switchPage(mustSwitch,upgradePage);

//	function toggle display of target page element id dependent on object test
function toggleBlock(targetId){
	if(document.getElementById){
			targetEl=document.getElementById(targetId);
		if(targetEl.style.display=="none"){
			targetEl.style.display="block";
		}else{
			targetEl.style.display="none";
		}
	}
}

// function doublechecks that keypressed is enter key
function verifyKey(el,ev){
  if(ev.keyCode == 13 && el.onClick){
    el.onClick();
  }
}