function key_press(event)
{
	event = (event) ? event : ((window.event) ? event : null);

	if (event) {
		key = (event.charCode) ? event.charCode : ((event.which) ? event.which : event.keyCode);
		if (String.fromCharCode(key).toLowerCase() == 'n') { // next image
			// Check for link to next image
			var next_link = document.getElementById('nextlink');
			if (next_link && next_link.href) {
				document.location.href = next_link.href;
			}
		} else if (String.fromCharCode(key).toLowerCase() == 'p') { // previous image
			// Check for link to previous image
			var prev_link = document.getElementById('prevlink');
			if (prev_link && prev_link.href) {
				document.location.href = prev_link.href;
			}
		}
	}	
}

if (document.addEventListener) {
	document.addEventListener('keypress', key_press, false);
} else if (document.attachEvent) {
	document.attachEvent('onkeypress', key_press);
} else {
	document.onkeypress = key_press;
}