[Azazaza]

о, нашел рабочий код)

$("#searchBtn").click(function () {var phrase = $('#searchBtn').prev('input').val(); 
   jQuery(":contains("+phrase+")").not(":has(:contains("+phrase+"))").each(function () {
      var that = $(this);
      var html = that.html();
 
      html = html.replace(new RegExp(phrase, 'gi'), '<span class="light">'+phrase+'</span>');
      that.html(html);
   });
});

всем спасибо)