function confirm_logout() {
		var message = "Logging out now will mean that your answers to this section will not be saved.\n\nAre you sure you want to log out?";
		if ( confirm( message ) ) {
			return true;
		} else {
			return false;
		}	
	}

//	open external links in a new window - replaces target="_blank"
	function externalLinks () { 
		if ( ! document.getElementsByTagName ) return; 
		var anchors = document.getElementsByTagName("a"); 
		for ( var i=0; i < anchors.length; i++ ) { 
			var anchor = anchors[i]; 
			if ( anchor.getAttribute("href") && anchor.getAttribute("rel") == "external" ) anchor.target = "_blank"; 
		} 
	} 

//	preload images
	function preload_images () {
		arImageSrc = new Array ();
		arImageList = new Array ();
		for (counter in arImageSrc) {
			arImageList[counter] = new Image();
			arImageList[counter].src = arImageSrc[counter];
		}
	}


//	add given page to favourites (bookmark)
	function setBookmark ( url, str ) {
		if ( str == '' ) str = url;
		if ( document.all ) window.external.AddFavorite( url, str );
		else alert( 'Sorry, this function only works in Internet Explorer.\n\nPlease press CTRL and D to add a bookmark to \n"' + str + '".' );
	}

//	toggle a given elements visibility
	function toggle (el) {
		if ( document.getElementById(el).style.display == 'none' ) {
			document.getElementById(el).style.display = '';
		} else {
			document.getElementById(el).style.display = 'none';
		}
	}

//	hide a given element
	function hide (el) {
		if ( document.getElementById(el) != undefined ) document.getElementById(el).style.display = 'none';
	}


//	show a given element
	function show (el) {
		if ( document.getElementById(el) != undefined ) document.getElementById(el).style.display = '';
	}
	
//	show a navigation item
	function show_nav(el) {
		if ( document.getElementById(el) != undefined ) {
			document.getElementById(el).src = 'media/images/' + el + '_o.jpg';
		}
	}

//	restore a navigation item
	function restore_nav(el) {
		if ( document.getElementById(el) != undefined ) {
			document.getElementById(el).src = 'media/images/' + el + '.jpg';
		}
		activate_nav();
	}

//	activate the current navigation item
	function activate_nav() {
		var fullpath = location.pathname;
		var patharray = fullpath.split('/');
		var folderposition = patharray.length - 1;
		var filename = patharray[folderposition];
		var filearray = filename.split('.');
		var nav = filearray[0];
		if ( nav == 'index' || nav == '' ) nav = 'home';
		if ( document.getElementById('nav_' + nav) != undefined ) {
			document.getElementById('nav_' + nav).src = 'media/images/nav_' + nav + '_o.jpg';
		}
		if ( document.getElementById('nav_admin_' + nav ) != undefined ) {
			document.getElementById('nav_admin_' + nav).className = 'selected';
		}
	}

//	perform the following functions when the page loads
	window.onload = function(e) {
		externalLinks();
		activate_nav();
	}