text: (function() {
    'use strict';
  
    // Parses versions in URL segments like:
    // "3", "dev", "release/2.7" or "3.6rc2"
    var version_regexs = [
      '(?:\\d)',
      '(?:\\d\\.\\d[\\w\\d\\.]*)',
      '(?:dev)',
      '(?:release/\\d.\\d[\\x\\d\\.]*)'];
  
    var all_versions = {
      '3.7': 'dev (3.7)',
      '3.6': '3.6',
      '3.5': '3.5',
      '2.7': '2.7',
    };
  
    var all_languages = {
        'en': 'English',
        'fr': 'French',
        'ja': 'Japanese',
    };
  
    function build_version_select(current_version, current_release) {
      var buf = ['<select>'];
  
      $.each(all_versions, function(version, title) {
        buf.push('<option value="' + version + '"');
        if (version == current_version)
          buf.push(' selected="selected">' + current_release + '</option>');
        else
          buf.push('>' + title + '</option>');
      });
  
      buf.push('</select>');
      return buf.join('');
    }
  
    function build_language_select(current_language) {
      var buf = ['<select>'];
  
      $.each(all_languages, function(language, title) {
        if (language == current_language)
          buf.push('<option value="' + language + '" selected="selected">' +
                   all_languages[current_language] + '</option>');
        else
          buf.push('<option value="' + language + '">' + title + '</option>');
      });
      buf.push('</select>');
      return buf.join('');
    }
  
    function navigate_to_first_existing(urls) {
      // Navigate to the first existing URL in urls.
      var url = urls.shift();
      if (urls.length == 0) {
        window.location.href = url;
        return;
      }
      $.ajax({
        url: url,
        success: function() {
          window.location.href = url;
        },
        error: function() {
          navigate_to_first_existing(urls);
        }
      });
    }
  
    function on_version_switch() {
      var selected_version = $(this).children('option:selected').attr('value') + '/';
      var url = window.location.href;
      var current_language = language_segment_from_url(url);
      var current_version = version_segment_in_url(url);
      var new_url = url.replace('.org/' + current_language + current_version,
                                '.org/' + current_language + selected_version);
      if (new_url != url) {
        navigate_to_first_existing([
          new_url,
          url.replace('.org/' + current_language + current_version,
                      '.org/' + selected_version),
          'https://docs.python.org/' + current_language + selected_version,
          'https://docs.python.org/' + selected_version,
          'https://docs.python.org/'
        ]);
      }
    }
  
    function on_language_switch() {
      var selected_language = $(this).children('option:selected').attr('value') + '/';
      var url = window.location.href;
      var current_language = language_segment_from_url(url);
      var current_version = version_segment_in_url(url);
      if (selected_language == 'en/') // Special 'default' case for english.
        selected_language = '';
      var new_url = url.replace('.org/' + current_language + current_version,
                                '.org/' + selected_language + current_version);
      if (new_url != url) {
        navigate_to_first_existing([
          new_url,
          'https://docs.python.org/'
        ]);
      }
    }
  
    // Returns the path segment of the language as a string, like 'fr/'
    // or '' if not found.
    function language_segment_from_url(url) {
      var language_regexp = '\.org/([a-z]{2}(?:-[a-z]{2})?/)';
      var match = url.match(language_regexp);
      if (match !== null)
          return match[1];
      return '';
    }
  
    // Returns the path segment of the version as a string, like '3.6/'
    // or '' if not found.
    function version_segment_in_url(url) {
      var language_segment = '(?:[a-z]{2}(?:-[a-z]{2})?/)';
      var version_segment = '(?:(?:' + version_regexs.join('|') + ')/)';
      var version_regexp = '\\.org/' + language_segment + '?(' + version_segment + ')';
      var match = url.match(version_regexp);
      if (match !== null)
        return match[1];
      return ''
    }
  
    $(document).ready(function() {
      var release = DOCUMENTATION_OPTIONS.VERSION;
      var language_segment = language_segment_from_url(window.location.href);
      var current_language = language_segment.replace(/\/+$/g, '') || 'en';
      var version = release.substr(0, 3);
      var version_select = build_version_select(version, release);
  
      $('.version_switcher_placeholder').html(version_select);
      $('.version_switcher_placeholder select').bind('change', on_version_switch);
  
      var language_select = build_language_select(current_language);
  
      $('.language_switcher_placeholder').html(language_select);
      $('.language_switcher_placeholder select').bind('change', on_language_switch);
    });
  })();
  