document.onkeydown = navigate;

function navigate (event) {
	if (!document.getElementById) {
		return;
	}

	if (window.event) {
		event = window.event;
	}

	if (event.ctrlKey) {
		var link = null;
		var href = null;
		switch (event.keyCode ? event.keyCode : event.which ? event.which : null) {
			case 0x25:
				link = document.getElementById ('prev');
				break;
			case 0x27:
				link = document.getElementById ('next');
				break;
		}

		if (link && link.href) document.location = link.href;
	}
}