gistfile1.js

var myName = 'Sumhat';
var myEmail = 'sumhat@gmail.com';
var myUrl = 'http://leonax.net';

function fillForm(blogIdSelector, authorSelector, urlSelector, emailSelector) {
  if (blogIdSelector != null) {
    var blogId = document.querySelector(blogIdSelector);
    if (blogId == null) {
      return false;
    }
  }
  var author = document.querySelector(authorSelector);
  if (author == null) {
    return false;
  }
  author.setAttribute('value', myName);
  var url = document.querySelector(urlSelector);
  if (url != null) {
    url.setAttribute('value', myUrl);
  }
  var email = document.querySelector(emailSelector);
  if (email == null) {
    return false;
  }
  email.setAttribute('value', myEmail);
  return true;
}
var blogList = {
  'wordpress': function() {return fillForm('#commentform', '#author', '#url', '#email');},
  'typecho': function() {return fillForm('#comment_form', '#author', '#url', '#mail');},
  'z_blog': function() {return fillForm('#frmSumbit', '#inpName', '#inpHomePage', '#inpEmail');},
  'emlog': function() {return fillForm('#commentform', 'input[name="comname"]', 'input[name="comurl"]', 'input[name="commail"]');}
};
for (var i in blogList) {
  if (blogList[i]()) {
    break;
  }
}