web前端js实现倒计时效果

var header_timer;
var current_timer;
var intDiff = 300;
function timer(intDiff){
current_timer =   window.setInterval(function(){
var     day=0,
hour=0,
minute=0,
second=0;
if(intDiff > 0){
minute = Math.floor(intDiff / 60) - (day * 24 * 60) - (hour * 60);
second = Math.floor(intDiff) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60);
}
if(intDiff==0) {
$("#wx_img_src img").attr("src","/static/images/whchar_art.jpg");
$("#ai_img_src img").attr("src","/static/images/whchar_art.jpg");
}
if (minute <= 9) minute = '0' + minute;
if (second <= 9) second = '0' + second;
$('.minute_time').html('<s></s>'+minute+'分');
$('.second_time').html('<s></s>'+second+'秒');
intDiff--;
}, 1000);
header_timer = current_timer;
}

var reslut="请在<strong class='minute_time'>分</strong>"
+"<strong class='second_time'>秒</strong>"
+"内扫二微码,否则将会失效。";
if (platCode == "XINBPAY" || platCode == "DINPAYWX") {
timer(intDiff);
$("#wx_img_src").html("");
$('#qrcode').qrcode({text: data.obj,width: 200,height: 200});
$(".wx_img_tips").html(reslut);
}else{
timer(intDiff);
$('#qrcode').html("");
$(".wx_img").css("display","block");
$("#wx_img_src img").attr("src",data.obj);
$(".wx_img_tips").html(reslut);
}