A smart dashboard have my id

// ==UserScript==
// @name           A smart dashboard have my id
// @namespace      jp.mitukiii.tumblr
// @include        http*://www.tumblr.com/dashboard*
// ==/UserScript==
(function() {
  
  var getMyId = document.getElementsByName("t")[0].value;  
  var isPost = function(elem) {
    return !!elem.id.match(/^post[0-9]+$/i);
  };
  
  var replaceClassName = function(post) {
    if (post.className.match(/not_mine/i)) {
      post.className = post.className.replace(/not_mine/i, 'is_mine');
    } else {
      post.className += ' is_mine';
    };
  };
  
  var replaceClassNameIfNotesHaveMyId = function(post) {
  
    var post_info = post.getElementsByClassName('post_info')[0];
    if (post_info.textContent.match(/reblogged you/i)) {
      return replaceClassName(post);
    };
  
    var blogs = post.getElementsByClassName('tumblr_blog');
    for (var i = 0, len = blogs.length, blog = null; i < len; i += 1) {
      blog = blogs[i];
      if (blog.textContent == getMyId()) {
        return replaceClassName(post);
      };
    };
    
  };
  
  (function() {
    var posts = document.getElementsByClassName('post');
    for (var i = 0, len = posts.length, post = null; i < len; i += 1) {
      post = posts[i];
      if (isPost(post)) {
        replaceClassNameIfNotesHaveMyId(post);
      };
    };
  })();
  
  document.addEventListener('DOMNodeInserted', function(event) {
    var elem = event.target;
    if (isPost(elem)) {
      replaceClassNameIfNotesHaveMyId(elem);
    };
  }, false);
  
})();