function hotkeys(e) {
	if (!e) e = window.event;
	var k = e.keyCode;
	var elem = 0;
	if (e.ctrlKey) {
		if (k == 37) {
			elem = document.getElementById('previous_page');
		} else if (k == 39) {
			elem = document.getElementById('next_page');
		}
  }
  if (elem) 
		location.href = elem.href;
}

function initHotkeys() {
  document.onkeydown = hotkeys;
}