function countdown(that) {
 var second = that.data.second
 if (second == 0) {
 // console.log("Time Out...");
 that.setData({
 second: "Time Out..."
 });
 return ;
 }
 var time = setTimeout(function(){
 that.setData({
 second: second - 1
 });
 countdown(that);
 }
 ,1000)
}
 
Page({
 data: {
 second: 3
 },
 onLoad: function() {
 countdown(this);
 }
});

/* 秒級(jí)倒計(jì)時(shí) */
function countdown(that) {
 var second = that.data.second
 if (second == 0) {
 that.setData({
 second: "Time out!",
 micro_second: "micro_second too."
 });
 clearTimeout(micro_timer);
 return ;
 }
 var timer = setTimeout(function(){
 that.setData({
 second: second - 1
 });
 countdown(that);
 }
 ,1000)
}
 
/* 毫秒級(jí)倒計(jì)時(shí) */
// 初始毫秒數(shù)，同時(shí)用作歸零
var micro_second_init = 100;
// 當(dāng)前毫秒數(shù)
var micro_second_current = micro_second_init;
// 毫秒計(jì)時(shí)器
var micro_timer;
 
function countdown4micro(that) {
 if (micro_second_current <= 0) {
 micro_second_current = micro_second_init;
 }
 micro_timer = setTimeout(function(){
 that.setData({
 micro_second: micro_second_current - 1
 });
 micro_second_current--;
 countdown4micro(that);
 }
 ,10)
}
 
Page({
 data: {
 second: 2,
 micro_second: micro_second_init
 },
 onLoad: function() {
 countdown(this);
 countdown4micro(this);
 }
});

<text style="display: block;">second: {{second}}s</text>
 
<text>{{micro_second}}</text>

function dateformat(second) {
 var dateStr = "";
 var hr = Math.floor(second / 3600);
 var min = Math.floor((second - hr * 3600) / 60);
 var sec = (second - hr * 3600 - min * 60);// equal to => var sec = second % 60;
 dateStr = hr + ":" + min + ":" + sec;
 return dateStr;
}
//目前有2個(gè)時(shí)鐘，影響性能，合并下去掉countdown，于是countdown4micro變成以下的樣子：
 
function countdown4micro(that) {
 
 var loop_second = Math.floor(loop_index / 100);
 // 得知經(jīng)歷了1s
 if (cost_micro_second != loop_second) {
 // 賦予新值
 cost_micro_second = loop_second;
 // 總秒數(shù)減1
 total_second--;
 
 }
 // 每隔一秒，顯示值減1; 渲染倒計(jì)時(shí)時(shí)鐘
 that.setData({
 clock:dateformat(total_second - 1)
 });
 
 if (total_second == 0) {
 that.setData({
 // micro_second: "",
 clock:"時(shí)間到"
 });
 clearTimeout(micro_timer);
 return ;
 } 
 
 if (micro_second_current <= 0) {
 micro_second_current = micro_second_init;
 }
 micro_timer = setTimeout(function(){
 that.setData({
 micro_second: micro_second_current - 1
 });
 micro_second_current--;
 // 放在最后++，不然時(shí)鐘停止時(shí)還有10毫秒剩余
 loop_index ++;
 countdown4micro(that);
 }
 ,10)
}

/** 
 * 需要一個(gè)目標(biāo)日期，初始化時(shí)，先得出到當(dāng)前時(shí)間還有剩余多少秒
 * 1.將秒數(shù)換成格式化輸出為XX天XX小時(shí)XX分鐘XX秒 XX
 * 2.提供一個(gè)時(shí)鐘，每10ms運(yùn)行一次，渲染時(shí)鐘，再總ms數(shù)自減10
 * 3.剩余的秒次為零時(shí)，return，給出tips提示說(shuō)，已經(jīng)截止
 */
 
// 定義一個(gè)總毫秒數(shù)，以一分鐘為例。TODO，傳入一個(gè)時(shí)間點(diǎn)，轉(zhuǎn)換成總毫秒數(shù)
var total_micro_second = 2 * 1000;
 
/* 毫秒級(jí)倒計(jì)時(shí) */
function countdown(that) {
 // 渲染倒計(jì)時(shí)時(shí)鐘
 that.setData({
 clock:dateformat(total_micro_second)
 });
 
 if (total_micro_second <= 0) {
 that.setData({
 clock:"已經(jīng)截止"
 });
 // timeout則跳出遞歸
 return ;
 } 
 setTimeout(function(){
 // 放在最后--
 total_micro_second -= 10;
 countdown(that);
 }
 ,10)
}
 
// 時(shí)間格式化輸出，如3:25:19 86。每10ms都會(huì)調(diào)用一次
function dateformat(micro_second) {
 // 秒數(shù)
 var second = Math.floor(micro_second / 1000);
 // 小時(shí)位
 var hr = Math.floor(second / 3600);
 // 分鐘位
 var min = Math.floor((second - hr * 3600) / 60);
 // 秒位
 var sec = (second - hr * 3600 - min * 60);// equal to => var sec = second % 60;
 // 毫秒位，保留2位
 var micro_sec = Math.floor((micro_second % 1000) / 10);
 return hr + ":" + min + ":" + sec + " " + micro_sec;
}
 
Page({
 data: {
 clock: ''
 },
 onLoad: function() {
 countdown(this);
 }
});