title: Cannot submit form with CasperJS - in other words cannot login
body: <p>I'm trying to login into Tumblr with CasperJS using methods <code>start</code>, <code>fill</code> and <code>waitForUrl</code> but <strong>cannot</strong> do this. <strong>It seems to me that form wasn't submitted</strong>, because timeout in <code>waitForUr</code> expired everytime.</p>
  
  <p><em>Terminal response:</em><br>
  <img src="https://content.screencast.com/users/yaajing/folders/Jing/media/60d5ab71-d2fe-4b98-af64-d742b90eb153/00000506.png" alt=""></p>
  
  <p><em>Code I'm using is this:</em></p>
  
  <pre><code>/*jslint browser: true, regexp: true */
  // global casper, require 
  
  var LOGIN_URL, LOGIN_USERNAME, LOGIN_PASSWORD, casper;
  
  casper = require('casper').create({
      waitTimeout: 20000,
      viewportSize: {
          width: 1024,
          height: 768
      },
      verbose: true,
      logLevel: 'debug',
      userAgent: 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)'
  });
  
  if (!casper.cli.has('username') &amp;&amp; !casper.cli.has('password')) {
      casper.echo('Usage: $ casperjs sfdclogin.casper.js --username=USERNAME --password=PASSWORD').exit(-1);
  }
  
  LOGIN_URL = 'https://tumblr.com/login';
  
  LOGIN_USERNAME = casper.cli.get('username');
  LOGIN_PASSWORD = casper.cli.get('password');
  
  phantom.cookiesEnabled = true;
  
  casper
      .start(LOGIN_URL, function () {
          // 'use strict';
  
          this.log('Logging in', 'debug');
          /*
          this.fillSelectors('#signup_form_form', {
              '#signup_email': LOGIN_USERNAME,
              '#signup_password': LOGIN_PASSWORD
          }, true);
          */
  
          this.fill('#signup_form_form', {
              '#user[email]': LOGIN_USERNAME,
              '#user[password]': LOGIN_PASSWORD
          }, true);
      })
  
      .waitForUrl('http://tumblr.com/dashboard', function () {
          // 'use strict';
  
          this.echo('We\'re logged in.');
      })
  
      .run();
  </code></pre>
  
  <p><em>Also</em>, I'm using correct username and password with this script.</p>