尝试创建测验计时器

Question

var myVar = setInterval(function() {
    myTimer()
}, 1000);
var d = 1;
function myTimer() {
    document.getElementById("demo").innerHTML = d++;
}

我正在尝试创建一个测验应用程序，我需要为数据库中已有的问题运行计时器。

我必须从数据库中检索时间，并运行倒计时计时器。

Answer 1

function myTimer(d) {
  d++;
  document.getElementById("demo").innerHTML = d;
  return d;
}

var d = 1;

var myVar = setInterval(function() {
  d = myTimer(d);
}, 1000);

像这样？

[阅读评论后编辑：]

var endpoint = [php_timestamp_here];
var countdown = setInterval(function() {
  var d = new Date();
  var ts = d.getTime();
  if( ts >= endpoint ){
    // stuff after reach the point...
    clearInterval(countdown);
  }
  // stuff every second
}, 1000);

Answer 2

像这样的东西呢。它没有回答计时器是完美的。

var running = false;
var timeToRun = 10000;  // 10 seconds
var startTime;
var timer;
var output = document.getElementById("output");


function start(){
    running = true;
    startTime = new Date();
    timer = setInterval(check, 100);
    output.innerHTML = "Started<br>" + output.innerHTML;
}

function stop(){
    running = false;
    clearInterval(timer);
}

function check(){
    var now = new Date();
    var left =  (startTime - now) + timeToRun;
    output.innerHTML = left + "<br>" + output.innerHTML; 

    if (left < 0){
        stop();
        output.innerHTML = "times up <br>" + output.innerHTML; 
    }
} 

start();

<div id="output">o</div>