Highlighting the current gutter for CordeMirror

gistfile1.js

function highlightingCurrentGutter(editor){
  var $collection_pre = $(editor.getGutterElement()).find('pre');
  $collection_pre.removeClass('active-gutter');
  $($collection_pre[editor.getCursor().line]).addClass('active-gutter');
}

/* exemple d'utilisation */
html_editor = CodeMirror.fromTextArea(html_code, {
  lineNumbers: true,
  matchBrackets: true,
  onCursorActivity: function() { highlightingCurrentGutter(html_editor); },
  mode:
  {
    name: 'xml',
    json: true
  },
  indentUnit: 2,
  theme: 'html',
  onKeyEvent: sendCodeToRendu
});