找一张想要替换的三角形图片,给下拉框添加初始事件,修改对应的css
setInterval(function(){
$(".fr-trigger-center").css("background", "url('/webroot/help/picture/sjx.png') no-repeat 0 0");
$(".fr-trigger-center").css("height", "18px");
$(".fr-trigger-center").css("margin-top", "18px");
},100)