$(function(){    var href = window.location.href.split('/')[window.location.href.split('/').length-1].substr(0,4);    if(href.length > 0){        $(function(){            $("ul.nav a:first[href^='"+href+"']").attr("class","on");            if($("ul.nav a:first[href^='"+href+"']").size() == 0){                $("ul.nav a:first[href^='index']").attr("class","on");            }        });    }else{        $(function(){$("ul.nav a:first[href^='index']").attr("class","on")});    }})

截取URL最后4位对比导航中A标签链接相同的元素加on样式