Bar*_*tek 217 javascript timer countdown countdowntimer
只是想问一下如何创建最简单的倒数计时器.
网站上会有一句话说:
"注册于05:00关闭!"
所以,我想要做的是创建一个简单的js倒计时器,从"05:00"到"00:00",然后一旦结束就重置为"05:00".
我以前经历过一些答案,但是对于我想做的事情,它们看起来都太强烈了(Date对象等).
rob*_*bmj 432
我有两个演示,一个有jQuery一个,一个没有.既没有使用日期功能,也没有使用日期功能.
function startTimer(duration, display) {
var timer = duration, minutes, seconds;
setInterval(function () {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ":" + seconds;
if (--timer < 0) {
timer = duration;
}
}, 1000);
}
window.onload = function () {
var fiveMinutes = 60 * 5,
display = document.querySelector('#time');
startTimer(fiveMinutes, display);
};<body>
<div>Registration closes in <span id="time">05:00</span> minutes!</div>
</body>function startTimer(duration, display) {
var timer = duration, minutes, seconds;
setInterval(function () {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.text(minutes + ":" + seconds);
if (--timer < 0) {
timer = duration;
}
}, 1000);
}
jQuery(function ($) {
var fiveMinutes = 60 * 5,
display = $('#time');
startTimer(fiveMinutes, display);
});
但是,如果您想要一个更复杂的更准确的计时器:
function startTimer(duration, display) {
var start = Date.now(),
diff,
minutes,
seconds;
function timer() {
// get the number of seconds that have elapsed since
// startTimer() was called
diff = duration - (((Date.now() - start) / 1000) | 0);
// does the same job as parseInt truncates the float
minutes = (diff / 60) | 0;
seconds = (diff % 60) | 0;
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ":" + seconds;
if (diff <= 0) {
// add one second so that the count down starts at the full duration
// example 05:00 not 04:59
start = Date.now() + 1000;
}
};
// we don't want to wait a full second before the timer starts
timer();
setInterval(timer, 1000);
}
window.onload = function () {
var fiveMinutes = 60 * 5,
display = document.querySelector('#time');
startTimer(fiveMinutes, display);
};<body>
<div>Registration closes in <span id="time"></span> minutes!</div>
</body>现在我们已经制作了一些非常简单的计时器,我们可以开始考虑可重用性和分离问题.我们可以通过询问"倒计时器应该做什么来做到这一点"来做到这一点.
所以记住这些事情让我们写得更好(但仍然非常简单) CountDownTimer
function CountDownTimer(duration, granularity) {
this.duration = duration;
this.granularity = granularity || 1000;
this.tickFtns = [];
this.running = false;
}
CountDownTimer.prototype.start = function() {
if (this.running) {
return;
}
this.running = true;
var start = Date.now(),
that = this,
diff, obj;
(function timer() {
diff = that.duration - (((Date.now() - start) / 1000) | 0);
if (diff > 0) {
setTimeout(timer, that.granularity);
} else {
diff = 0;
that.running = false;
}
obj = CountDownTimer.parse(diff);
that.tickFtns.forEach(function(ftn) {
ftn.call(this, obj.minutes, obj.seconds);
}, that);
}());
};
CountDownTimer.prototype.onTick = function(ftn) {
if (typeof ftn === 'function') {
this.tickFtns.push(ftn);
}
return this;
};
CountDownTimer.prototype.expired = function() {
return !this.running;
};
CountDownTimer.parse = function(seconds) {
return {
'minutes': (seconds / 60) | 0,
'seconds': (seconds % 60) | 0
};
};
那么为什么这种实现比其他实现更好？以下是您可以使用它做些什么的一些示例.请注意,除了第一个示例之外的所有示例都无法通过startTimer函数实现.
coc*_*cco 22
如果你想要一个真正的计时器,你需要使用日期对象.
计算差异.
格式化字符串.
window.onload=function(){
var start=Date.now(),r=document.getElementById('r');
(function f(){
var diff=Date.now()-start,ns=(((3e5-diff)/1e3)>>0),m=(ns/60)>>0,s=ns-m*60;
r.textContent="Registration closes in "+m+':'+((''+s).length>1?'':'0')+s;
if(diff>3e5){
start=Date.now()
}
setTimeout(f,1e3);
})();
}
例
不那么精确的计时器
var time=5*60,r=document.getElementById('r'),tmp=time;
setInterval(function(){
var c=tmp--,m=(c/60)>>0,s=(c-m*60)+'';
r.textContent='Registration closes in '+m+':'+(s.length>1?'':'0')+s
tmp!=0||(tmp=time);
},1000);
小智 13
您可以使用setInterval轻松创建计时器功能.Below是可用于创建计时器的代码.
http://jsfiddle.net/ayyadurai/GXzhZ/1/
window.onload = function() {
var hour = 2;
var sec = 60;
setInterval(function() {
document.getElementById("timer").innerHTML = hour + " : " + sec;
sec--;
if (sec == 00) {
hour--;
sec = 60;
if (hour == 0) {
hour = 2;
}
}
}, 1000);
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