Hatena Graph Previewer

hatena_graph_previewer.user.js

// ==UserScript==
// @name       Hatena Graph Previewer
// @namespace  http://twitter.com/m_satyr
// @include    http://graph.hatena.ne.jp/*/edit*
// @license    X
// ==/UserScript==
var gedit = document.getElementById('graphedit');
var table = gedit.querySelector('table');
var graph = gedit.appendChild(new Image);
var titles = document.getElementById('titlecel').children;
var iscell = /^t[hd]$/i;
var curidx = 1;

graph.id = 'graph';
preview({target: table.querySelector('th:nth-child(2)')});
table.addEventListener('mouseover', preview, false);
table.addEventListener('change', preview, false);

function preview(ev){
  var lm = ev.target;
  for(;; lm = lm.parentNode)
    if(lm == table) return;
    else if(iscell.test(lm.nodeName)) break;

  var sibs = lm.parentNode.children, len = sibs.length, idx = len;
  while(sibs[--idx] != lm);
  if(idx < 1 || len - 3 < idx ||
     idx == curidx && ev.type == 'mouseover') return;

  curidx = idx;
  setTimeout(function(){
    var name = graph.title = graph.alt = titles[idx].textContent.trim();
    graph.src = (/^\/[^/]+/(location.pathname) +'/graph?graphname='+
                 encodeURIComponent(name) +'&mode=detail&'+ Date.now());
  }, 9);
}

http://help-me-hackers.com/tasks/133