jQuery.fn.exists = function(){return jQuery(this).length>0;}

jQuery(document).ready(function() {
  if (jQuery("#level2 ul li").exists()){
    var total_left = jQuery("#main_menu a.active").offset().left;
    var leve2_left = jQuery("#level2").offset().left;
    jQuery("#level2 ul").css({"margin-left":total_left-leve2_left+2+"px"});
  }else{
    jQuery("#level2").hide();
  }    
  
  jQuery('a[rel=external]').attr("target","_blank");
  
});