function isset(varname){
  return(typeof(window[varname])!='undefined');
}

function flipper_which_active() {
	if (isset('flipper_content')) {
		var active = 1;

		for (var i=1; i<=(flipper_content.length-1); i++) {
			if (document.getElementById('flip'+i)) {
				if (document.getElementById('flip'+i).className == 'on')
					active = i;
			}
		}

		return active;
	}
}

function flipper_read(id) {
	if (isset('flipper_content')) {
		for (var i=1; i<=(flipper_content.length-1); i++) {
			if (document.getElementById('flip'+i)) {
				if (id == i)
					document.getElementById('flip'+i).className = 'on';
				else
					document.getElementById('flip'+i).className = '';
			}
		}

		if (document.getElementById('flipper_image')) document.getElementById('flipper_image').innerHTML = flipper_content[id][0];
		if (document.getElementById('flipper_text')) document.getElementById('flipper_text').innerHTML = flipper_content[id][1];
	}
}

function flipper_prev() {
	if (isset('flipper_content')) {
		var active = flipper_which_active();

		if (((active-1) < flipper_content.length) && (active > 1))
			flipper_read(active-1);
		else
			flipper_read(1);
	}
}

function flipper_next() {
	if (isset('flipper_content')) {
		var active = flipper_which_active();

		if (((active+1) < flipper_content.length) && (active > 0))
			flipper_read(active+1);
		else
			flipper_read(1);
	}
}

function flipper_generate_navigation() {
	if (isset('flipper_content')) {
		if (document.getElementById('flipper_navigation')) {
			document.getElementById('flipper_navigation').innerHTML = '';

			for (var i=1; i<=(flipper_content.length-1); i++) {
				document.getElementById('flipper_navigation').innerHTML += '<a href="javascript:flipper_read('+i+');" id="flip'+i+'">'+i+'</a>';
			}
		}
	}
}

window.onload = function() {
	if (isset('flipper_content')) {
		flipper_generate_navigation();
		flipper_read(1);
	}
}

var int = self.setInterval("flipper_next()", 10000);