// ==UserScript==
// @name          Jump to Flickr Page
// @namespace     http://www.dopiaza.org/flickr/greasemonkey/
// @description   Jump to a specific Flickr page in a paginated set of pages.
// @include       http://www.flickr.com/*
// @include       http://flickr.com/*
// ==/UserScript==

var paginators = document.evaluate(
  "//div[@class='Paginator']",
  document,
  null,
  XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE,
  null);

for (var i = 0; i < paginators.snapshotLength; i++)
{
  var paginator = paginators.snapshotItem(i);

  // Place the text box immediately before the "Next" item, which is the last 
  // non-text element in the paginator (There is whitespace after it, which shows
  // up as a text node). It may be an anchor or a span, depending on whether we are
  // at the last page or not.
  var paginatorChildren = paginator.childNodes;

  var nextElement;
  for (var j = paginatorChildren.length - 1; j >= 0; j--)
  {
    if (paginatorChildren[j].nodeType == 1) // Element Node
    {
      nextElement = paginatorChildren[j];
      break;
    }
  }

  var inputBox = document.createElement('input');
  inputBox.setAttribute("type", "text");
  inputBox.setAttribute("size", "3");

  paginator.insertBefore(inputBox, nextElement);
  
  inputBox.addEventListener('keypress', function(evt) 
  {
    var keyVal = evt.which;
    var key = String.fromCharCode(keyVal);

    if (key == '\r')
    {
      var pageNum = evt.target.value;

      // So, where are we now?
      var loc = window.location.href;
      // Remove any existing page number
      loc = loc.replace(/page\d+(\/)?$/, '');
      // Append the new page number
      loc += 'page' + pageNum + '/';
      // And go to the new page
      window.location.href = loc;
    }
    else
    {
      if (key != '\b' && isNaN(key))
      {
        evt.preventDefault();
      }
    }
  }, true);
}