function public_site_content(el) {
	var home = document.getElementById('sc_home');
	var activity_schedule = document.getElementById('sc_activity_schedule');
	var prices = document.getElementById('sc_prices');
	var directions = document.getElementById('sc_directions');
	var gallery = document.getElementById('sc_gallery');
	var terms = document.getElementById('sc_terms');

	var nav_home = document.getElementById('nav_sc_home');
	var nav_activity_schedule = document.getElementById('nav_sc_activity_schedule');
	var nav_prices = document.getElementById('nav_sc_prices');
	var nav_directions = document.getElementById('nav_sc_directions');
	var nav_gallery = document.getElementById('nav_sc_gallery');
	var nav_terms = document.getElementById('nav_sc_terms');
	
	home.style.display = 'none';
	activity_schedule.style.display = 'none';
	prices.style.display = 'none';
	directions.style.display = 'none';
	gallery.style.display = 'none';
	terms.style.display = 'none';
	
	nav_home.className = '';
	nav_activity_schedule.className = '';
	nav_prices.className = '';
	nav_directions.className = '';
	nav_gallery.className = '';
	nav_terms.className = '';
	
	var selected = document.getElementById('sc_'+el);
	var selected_nav = document.getElementById('nav_sc_'+el);
	selected.style.display = '';
	selected_nav.className = 'selected';

}

function show_site_content(el) {
	var introduction = document.getElementById('sc_introduction');
	var opening_times = document.getElementById('sc_opening_times');
	var activity_schedule = document.getElementById('sc_activity_schedule');
	var prices = document.getElementById('sc_prices');
	var directions = document.getElementById('sc_directions');
	var gallery = document.getElementById('sc_gallery');
	var jobs = document.getElementById('sc_jobs');

	var nav_introduction = document.getElementById('nav_sc_introduction');
	var nav_opening_times = document.getElementById('nav_sc_opening_times');
	var nav_activity_schedule = document.getElementById('nav_sc_activity_schedule');
	var nav_prices = document.getElementById('nav_sc_prices');
	var nav_directions = document.getElementById('nav_sc_directions');
	var nav_gallery = document.getElementById('nav_sc_gallery');
	var nav_jobs = document.getElementById('nav_sc_jobs');
	
	introduction.style.display = 'none';
	opening_times.style.display = 'none';
	activity_schedule.style.display = 'none';
	prices.style.display = 'none';
	directions.style.display = 'none';
	gallery.style.display = 'none';
	jobs.style.display = 'none';
	
	nav_introduction.className = '';
	nav_opening_times.className = '';
	nav_activity_schedule.className = '';
	nav_prices.className = '';
	nav_directions.className = '';
	nav_gallery.className = '';
	nav_jobs.className = '';
	
	var selected = document.getElementById('sc_'+el);
	var selected_nav = document.getElementById('nav_sc_'+el);
	selected.style.display = '';
	selected_nav.className = 'selected';

}

function swap_site_image(site) {
	var image = document.getElementById('high_sports');
	image.src = 'media/images/high_sports/high_sports_' + site + '.jpg';
}

function restore_site_image() {
	var image = document.getElementById('high_sports');
	image.src = 'media/images/high_sports/high_sports_home.jpg';
}

//	show the rota form
	function show_rota_form(session_id,date,start,end,user_id,rota_id) {
		var rota_form = document.getElementById('rota_form');
		rota_form.style.display = '';
		var fk_rota_session_id = document.getElementById('fk_rota_session_id');
		var fk_hs_user_id = document.getElementById('fk_hs_user_id');
		var date_field = document.getElementById('date');
		var start_hour_field = document.getElementById('start_hour');
		var start_minute_field = document.getElementById('start_minute');
		var end_hour_field = document.getElementById('end_hour');
		var end_minute_field = document.getElementById('end_minute');
		var rota_id_field = document.getElementById('rota_id');
		
		for ( var i = 0; i < fk_rota_session_id.options.length; i++ ) {
			if ( fk_rota_session_id.options[i].value == session_id ) fk_rota_session_id.options[i].selected = true;	
		}
		date_field.value = date;
		
		var start_array = start.split(':');
		var end_array = end.split(':');
		
		for ( var m = 0; m < start_hour_field.options.length; m++ ) {
			if ( start_hour_field.options[m].value == start_array[0] ) start_hour_field.options[m].selected = true;
		}
		for ( var n = 0; n < start_minute_field.options.length; n++ ) {
			if ( start_minute_field.options[n].value == start_array[1] ) start_minute_field.options[n].selected = true;
		}

		for ( var o = 0; o < end_hour_field.options.length; o++ ) {
			if ( end_hour_field.options[o].value == end_array[0] ) end_hour_field.options[o].selected = true;
		}
		for ( var p = 0; p < end_minute_field.options.length; p++ ) {
			if ( end_minute_field.options[p].value == end_array[1] ) end_minute_field.options[p].selected = true;
		}
		
		for ( var a = 0; a < fk_hs_user_id.options.length; a++ ) {
			if ( fk_hs_user_id.options[a].value == user_id ) fk_hs_user_id.options[a].selected = true;
		}
		rota_id_field.value = rota_id;
		
	}

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

//	bookmark a page
	function bookmark_page( url, title ) {
if (window.sidebar) // firefox
	window.sidebar.addPanel(title, url, "");
else if(window.opera && window.print){ // opera
	var elem = document.createElement('a');
	elem.setAttribute('href',url);
	elem.setAttribute('title',title);
	elem.setAttribute('rel','sidebar');
	elem.click();
} 
else if(document.all)// ie
	window.external.AddFavorite(url, title);
}


function bookmarksite(title,url){
if (window.sidebar) // firefox
	window.sidebar.addPanel(title, url, "");
else if(window.opera && window.print){ // opera
	var elem = document.createElement('a');
	elem.setAttribute('href',url);
	elem.setAttribute('title',title);
	elem.setAttribute('rel','sidebar');
	elem.click();
} 
else if(document.all)// ie
	window.external.AddFavorite(url, title);
}

//	limit number of characters in a textarea field
	function limit_characters( limit_field, limit_count_field, limit_num ) {
		var limit_field = document.getElementById(limit_field);
		var limit_count_field = document.getElementById(limit_count_field);
		if ( limit_field != undefined ) {
			if ( limit_field.value.length > limit_num ) {
				limit_field.value = limit_field.value.substring( 0, limit_num );
			} else {
				limit_count_field.innerHTML	= (limit_num - limit_field.value.length) + ' characters remaining';
			}		
		}	
	}


//	show events on the home page
		function show_events(type) {
			var type;
			var tab_summary = document.getElementById('tab_summary');
			var tab_water = document.getElementById('tab_water');
			var tab_ashore = document.getElementById('tab_ashore');
			var container_summary = document.getElementById('event_summary');
			var container_water = document.getElementById('event_water');
			var container_ashore = document.getElementById('event_ashore');
			switch ( type ) {
				case 'water' :
					tab_summary.className = 'off';
					tab_water.className = 'on';
					tab_ashore.className = 'off';
					container_summary.style.display = 'none';
					container_water.style.display = '';
					container_ashore.style.display = 'none';
					break;
				case 'ashore' :
					tab_summary.className = 'off';
					tab_water.className = 'off';
					tab_ashore.className = 'on';
					container_summary.style.display = 'none';
					container_water.style.display = 'none';
					container_ashore.style.display = '';
					break;
				default :
					tab_summary.className = 'on';
					tab_water.className = 'off';
					tab_ashore.className = 'off';
					container_summary.style.display = '';
					container_water.style.display = 'none';
					container_ashore.style.display = 'none';
					break;
					
			}
		}


//	when the search field gets the focus
	function search_focus() {
		var search = document.getElementById('q');
		if ( search.value == 'Search...' ) {
			search.value = '';
		} else {
			search.select();
		}
		search.className = 'field_search_focus';
	}
	
//	when the search field loses the focus
	function search_blur() {
		var search = document.getElementById('q');
		if ( search.value == '' ) {
			search.value = 'Search...';
		}
		search.className = 'field_search';
	}

// 	retrieve a url parameter
	function get_url_parameter( name ) {
		name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
		var regexS = "[\\?&]"+name+"=([^&#]*)";
		var regex = new RegExp( regexS );
		var results = regex.exec( window.location.href );
		if( results == null ) {
			return "";
		} else {
			return results[1];
		}
	}

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

//	convert date and time to unixtimestamp
	function date_to_unixtime(target_field, month_el, day_el, year_el, hour_el, minute_el) {
		var target = document.getElementById(target_field);
		var year = document.getElementById(year_el).value;
		var month = document.getElementById(month_el).value;
		var day = document.getElementById(day_el).value;
		var hour = document.getElementById(hour_el).value;
		var minute = document.getElementById(minute_el).value;
		var second = '01';
		
		var errors = 0;
		var error_message = 'The following elements appear to be missing or incorrect' + "\n";
		if ( year.length != 4 ) {
			error_message += ' - you must enter a 4 digit year' + "\n";
			errors = 1;
		}
		if ( month > 12 ) {
			error_message += ' - the month must be between 1 and 12' + "\n";
			errors = 1;
		}
		if ( day > 31 ) {
			error_message += ' - the day must be between 1 and 31' + "\n";
			errors = 1;
		}
		if ( hour > 24 ) {
			error_message += ' - the hour must be 24 hour (e.g. 13 = 1pm)' + "\n";
			errors = 1;
		}
		if ( minute > 59 ) {
			error_message += ' - the minutes must be between 0 and 59' + "\n";
			errors = 1;
		}
		if ( errors == 1 ) {
			alert( error_message );
		} else {
			var humDate = new Date(Date.UTC(year, (nozeros(month)-1), nozeros(day), nozeros(hour), nozeros(minute), nozeros(second))); 
			target.value = (humDate.getTime()/1000.0);
		}
	
	}

//	get the current page
	function get_current_page() {
		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];
		return nav;
	}

//	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"; 
		} 
	} 

//	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) == undefined ) return false;
		if ( document.getElementById(el).style.display == 'none' ) {
			document.getElementById(el).style.display = '';
		} else {
			document.getElementById(el).style.display = 'none';
		}
	}

//	show a given element
	function show (el) {
		if ( document.getElementById(el) != undefined ) document.getElementById(el).style.display = '';
	}

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

//	manage the show/hide buttons
	function showhide( source_el, target_el ) {
		var source = document.getElementById(source_el);
		var target = document.getElementById(target_el);
		toggle(target_el);
		if ( target.style.display == 'none' ) {
			source.innerHTML = 'Show &darr;';
			source.className = 'showhide';
		} else {
			source.innerHTML = 'Hide &uarr;';
			source.className = 'hideshow';
		}
	}


//	activate the correct navigation
	function activate_nav() {
		var nav = get_current_page();
		if ( nav == '' ) {
			nav = 'index';
		}
		if ( nav == 'search' || nav == 'email' ) {
			nav = 'blank';
		}
		var parent_page = nav;
		switch ( nav ) {
		

		
		}
		if ( document.getElementById('nav_' + parent_page) != undefined ) document.getElementById('nav_' + parent_page).className = 'selected';

		var show_menu = '';
		switch ( nav ) {
		
			case 'officers' :
			case 'facilities' :
			case 'history' :
			case 'membership_application' :
			case 'rules' :
			case 'merchandise' :
				show_menu = 'the_club';
				break;
				
			case 'calendar_water' :
			case 'sailing_instructions' :
			case 'racing_results' :
			case 'regattas' :
			case 'cruising' :
			case 'fleet' :
				show_menu = 'on_the_water';
				break;
				
			case 'calendar_ashore' :
			case 'opening_hours' :
			case 'club_events' :
				show_menu = 'ashore';
				break;
		
		}
//		document.getElementById('nav_'+show_menu).className = 'selected';

		

	}

//	make a textarea grow
	function extend_textarea(el) {
		if ( document.getElementById(el) == undefined ) return false;
		var el = document.getElementById(el);
		if ( el.value.length > 150 ) {
			el.style.height = "100px";
		} else {
			el.style.height = "50px";
		}
	}

//	populate a business card
	function populate_business_card(card_id,card_type) {
		xmlHttp = initiate_ajax();
		xmlHttp.onreadystatechange=function() {
			if(xmlHttp.readyState==4) {
				document.getElementById('business_card_content').innerHTML=xmlHttp.responseText;
			}
		}
		xmlHttp.open("GET","business_card.php?card_id=" + card_id + "&card_type=" + card_type,true);
		xmlHttp.send(null);
	}



//	initialise an httpRequest object
	function initiate_ajax() {
		var xmlHttp;
		try {

			// Firefox, Opera 8.0+, Safari
			xmlHttp=new XMLHttpRequest();
		}
		catch (e) {

			// Internet Explorer
			try {
				xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
			}
			catch (e) {
				try {
					xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
				}
				catch (e) {
					alert("Your browser does not support AJAX!");
					return false;
				}
			}
		}
		return xmlHttp;
	}


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