// ==UserScript==
// @name        Adapt ScrumGuides
// @namespace   se.wendt.scrumguides
// @include     http://scrumguides.org/*
// @version     1
// @grant       none
// ==/UserScript==
var a = function () {
  var getURLParam = function(name) {
    var search = window.location.search;
    var pairs = search.substr(1).split("&");
    for (var i = 0; i < pairs.length; i++) {
      var parts = pairs[i].split("=");
      if (parts[0] === name) {
        return parseInt(parts[1], 10);
      }
    }
  };
  
  // expects something like .../scrum-guide.html?offset=3&limit=6#events-sprint
  var nameOfReferenceElement = document.location.hash.substr(1);
  var nodesToHighlight = getURLParam('limit');
  var numberOfNodesToSkip = getURLParam('offset');

  var highlightFrom = function (node) {
    var nodesSkipped = 0;
    for (var i = 0; i < numberOfNodesToSkip; i++) {
      node = node.nextSibling;
    }
    for (i = 0; i < nodesToHighlight; i++) {
      node.style = 'background: yellow';
      node = node.nextSibling;
    }
  }

  var startElement = document.getElementsByName(nameOfReferenceElement);
  var anchors = document.getElementsByTagName('a');
  for (var i = 0; i < anchors.length; i++) {
    var anchor = anchors[i];
    if (anchor.name === nameOfReferenceElement) {
      return highlightFrom(anchor.parentNode);
    }
  }
};
a();