Integration with TinyMCE 4.x

In the TinyMCE init code, add the following line:

file_browser_callback : elFinderBrowser

Then add the following function (change the elfinder_url to the correct path on your system):

function elFinderBrowser (field_name, url, type, win) {
  tinymce.activeEditor.windowManager.open({
    file: '/elfinder/elfinder.html',// use an absolute path!
    title: 'elFinder 2.0',
    width: 900,  
    height: 450,
    resizable: 'yes'
  }, {
    setUrl: function (url) {
      win.document.getElementById(field_name).value = url;
    }
  });
  return false;
}

Create (or edit) elfinder.html file. Include jQuery, jQuery UI, and elFinder

<!-- Include jQuery, jQuery UI, elFinder (REQUIRED) -->

<script type="text/javascript">
  var FileBrowserDialogue = {
    init: function() {
      // Here goes your code for setting your custom things onLoad.
    },
    mySubmit: function (URL) {
      // pass selected file path to TinyMCE
      top.tinymce.activeEditor.windowManager.getParams().setUrl(URL);

      // close popup window
      top.tinymce.activeEditor.windowManager.close();
    }
  }

  $().ready(function() {
    var elf = $('#elfinder').elfinder({
      // set your elFinder options here
      url: 'php/connector.php',  // connector URL
      getFileCallback: function(file) { // editor callback
// actually file.url - doesnt work for me, but file does. (elfinder 2.0-rc1)
        FileBrowserDialogue.mySubmit(file); // pass selected file path to TinyMCE 
      }
    }).elfinder('instance');      
  });
</script>