function getTextNodesIn(el) {
    var exclude = 'iframe,pre,code';
    return $(el).find(':not('+exclude+')').andSelf().contents().filter(function() {
      return this.nodeType == 3 && $(this).closest(exclude).length === 0;
    });
  }
Fetches a given element from the DOM.

Returns a jQuery object.
@api private