$.fn.extend 为啥非得是fn
(function($){$.fn.extend({"focusColo":function(li_c){var li_over="#ccc";var li_out="#fff";li_c=(li_c==undefined)?li_over:li_c;$(this).find("li").each(function(){$(this).mouseover(function(){$(this).css("background-color",li_c);}).mouseout(function(){$(this).css("background-color","#fff");})})return $(this);}});})(jQuery);$(function(){$("ul").focusColo("red");})
