Extensions Docs Server: use addEventListener with branch.js

chrome/common/extensions/docs/server2/templates/private/header_body.html

 {{?branchInfo.showWarning}}
 <div id="branchWarning" class="displayModeWarning">
   <span>WARNING: this is the {{branchInfo.current}} documentation. It may not work with the stable release of Chrome.</span>
-  <select id="branchChooser" onchange="redirectToBranch(this.value)">
+  <select id="branchChooser">
     <option value="">Choose a different version...</option>
     {{#branchInfo.branches}}
     <option value="{{path}}">{{name}}</option>
     {{/}}
   </select>
 </div>
 {{/}}
 <a id="top"></a>
 <div id="skipto">
   <a href="#gc-pagecontent">Skip to page content</a>
@@ skipping 23 matching lines @@
       <a href="samples.html" title="Sample extensions (with source code)"><div>Samples</div></a>
     </li>
     <li id="group_link">
       <a href="http://groups.google.com/a/chromium.org/group/chromium-extensions" title="Google Chrome Extensions developer forum"><div>Group</div></a>
     </li>
     <li id="so_link">
       <a href="http://stackoverflow.com/questions/tagged/google-chrome-extension" title="[google-chrome-extension] tag on Stack Overflow"><div>Questions?</div></a>
     </li>
   </ul>
 </div>