// from http://www.dustindiaz.com/rock-solid-addevent/
function addEvent( obj, type, fn ) {
	if (obj.addEventListener) {
		obj.addEventListener( type, fn, false );
		EventCache.add(obj, type, fn);
	}
	else if (obj.attachEvent) {
		obj["e"+type+fn] = fn;
		obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
		obj.attachEvent( "on"+type, obj[type+fn] );
		EventCache.add(obj, type, fn);
	}
	else {
		obj["on"+type] = obj["e"+type+fn];
	}
}

var EventCache = function(){
	var listEvents = [];
	return {
		listEvents : listEvents,
		add : function(node, sEventName, fHandler){
			listEvents.push(arguments);
		},
		flush : function(){
			var i, item;
			for(i = listEvents.length - 1; i >= 0; i = i - 1){
				item = listEvents[i];
				if(item[0].removeEventListener){
					item[0].removeEventListener(item[1], item[2], item[3]);
				};
				if(item[1].substring(0, 2) != "on"){
					item[1] = "on" + item[1];
				};
				if(item[0].detachEvent){
					item[0].detachEvent(item[1], item[2]);
				};
				item[0][item[1]] = null;
			};
		}
	};
}();
if (document.all) { addEvent(window,'unload',EventCache.flush); }


function toggle_block (id)
{
	var el = document.getElementById(id);
	el.style.display = (el.style.display == 'none') ? '' : 'none';
}

// Simple Javascript Browser/OS detection (based on "Harald Hope, Tapio Markula, http://techpatterns.com ver 2.0.1")
var ua = navigator.userAgent;

var os_win = ( navigator.appVersion.indexOf( 'Win' ) != -1 );
var os_mac = ( navigator.appVersion.indexOf( 'Mac' ) != -1 );
var os_lin = ( ua.indexOf( 'Linux' ) != -1 );

var is_opera = ( ua.indexOf( 'Opera' ) != -1 );
var is_konq  = ( ua.indexOf( 'Konqueror' ) != -1 );
var is_saf   = ( ua.indexOf( 'Safari' ) != -1 );
var is_moz   = ( ua.indexOf( 'Gecko' ) != -1 && !is_saf && !is_konq);
var is_ie    = ( document.all && !is_opera );
var is_ie4   = ( is_ie && !document.getElementById );

// ie5x tests only for functionality
// Opera will register true in this test if set to identify as IE 5
var is_ie5x    = ( document.all && document.getElementById );
var os_ie5mac  = ( os_mac && is_ie5x );
var os_ie5xwin = ( os_win && is_ie5x );