在运行时更改SetInterval的间隔

Question

我编写了一个javascript函数,它使用setInterval在十分之一秒内操作一个字符串,进行一定次数的迭代.

function timer() {
    var section = document.getElementById('txt').value;
    var len = section.length;
    var rands = new Array();

    for (i=0; i<len; i++) {
        rands.push(Math.floor(Math.random()*len));
    };

    var counter = 0
    var interval = setInterval(function() {
        var letters = section.split('');
        for (j=0; j < len; j++) {
            if (counter < rands[j]) {
                letters[j] = Math.floor(Math.random()*9);
            };
        };
        document.getElementById('txt').value = letters.join('');
        counter++

        if (counter > rands.max()) {
            clearInterval(interval);
        }
    }, 100);
};

我没有将间隔设置为特定的数字,而是希望在每次运行时根据计数器更新它.所以代替:

var interval = setInterval(function() { ... }, 100);

它会是这样的:

var interval = setInterval(function() { ... }, 10*counter);

不幸的是,这不起作用.似乎"10*counter"等于0.

那么,每次匿名函数运行时如何调整间隔？

Answer 1

您可以使用匿名函数:

var counter = 10;
var myFunction = function(){
    clearInterval(interval);
    counter *= 10;
    interval = setInterval(myFunction, counter);
}
var interval = setInterval(myFunction, counter);

更新:根据A. Wolff的建议,使用setTimeout以避免需要clearInterval.

var counter = 10;
var myFunction = function() {
    counter *= 10;
    setTimeout(myFunction, counter);
}
setTimeout(myFunction, counter);

Answer 2

请setTimeout()改用.然后回调将负责触发下一个超时,此时您可以增加或以其他方式操纵时序.

编辑

这是一个通用函数,可用于为任何函数调用应用"减速"超时.

function setDeceleratingTimeout(callback, factor, times)
{
    var internalCallback = function(tick, counter) {
        return function() {
            if (--tick >= 0) {
                window.setTimeout(internalCallback, ++counter * factor);
                callback();
            }
        }
    }(times, 0);

    window.setTimeout(internalCallback, factor);
};

// console.log() requires firebug    
setDeceleratingTimeout(function(){ console.log('hi'); }, 10, 10);
setDeceleratingTimeout(function(){ console.log('bye'); }, 100, 10);

Answer 3

我喜欢这个问题 - 在我身上启发了一个小计时器对象:

window.setVariableInterval = function(callbackFunc, timing) {
  var variableInterval = {
    interval: timing,
    callback: callbackFunc,
    stopped: false,
    runLoop: function() {
      if (variableInterval.stopped) return;
      var result = variableInterval.callback.call(variableInterval);
      if (typeof result == 'number')
      {
        if (result === 0) return;
        variableInterval.interval = result;
      }
      variableInterval.loop();
    },
    stop: function() {
      this.stopped = true;
      window.clearTimeout(this.timeout);
    },
    start: function() {
      this.stopped = false;
      return this.loop();
    },
    loop: function() {
      this.timeout = window.setTimeout(this.runLoop, this.interval);
      return this;
    }
  };

  return variableInterval.start();
};

使用示例

var vi = setVariableInterval(function() {
  // this is the variableInterval - so we can change/get the interval here:
  var interval = this.interval;

  // print it for the hell of it
  console.log(interval);

  // we can stop ourselves.
  if (interval>4000) this.stop();

  // we could return a new interval after doing something
  return interval + 100;
}, 100);  

// we can change the interval down here too
setTimeout(function() {
  vi.interval = 3500;
}, 1000);

// or tell it to start back up in a minute
setTimeout(function() {
  vi.interval = 100;
  vi.start();
}, 60000);

Answer 4

我和原始海报有同样的问题,这是一个解决方案.不确定这是多么有效....

interval = 5000; // initial condition
var run = setInterval(request , interval); // start setInterval as "run"

    function request() { 

        console.log(interval); // firebug or chrome log
        clearInterval(run); // stop the setInterval()

         // dynamically change the run interval
        if(interval>200 ){
          interval = interval*.8;
        }else{
          interval = interval*1.2;
        }

        run = setInterval(request, interval); // start the setInterval()

    }

Answer 5

一种更简单的方法是if在刷新的函数中使用一个语句,并以一个控制来定期执行命令.在以下示例中,我每2秒运行一次警报,并且intrv可以动态更改interval()...

var i=1;
var intrv=2; // << control this variable

var refreshId = setInterval(function() {
  if(!(i%intrv)) {
    alert('run!');
  }
  i++;
}, 1000);

Answer 6

这是我这样做的方式,我使用setTimeout:

var timer = {
    running: false,
    iv: 5000,
    timeout: false,
    cb : function(){},
    start : function(cb,iv){
        var elm = this;
        clearInterval(this.timeout);
        this.running = true;
        if(cb) this.cb = cb;
        if(iv) this.iv = iv;
        this.timeout = setTimeout(function(){elm.execute(elm)}, this.iv);
    },
    execute : function(e){
        if(!e.running) return false;
        e.cb();
        e.start();
    },
    stop : function(){
        this.running = false;
    },
    set_interval : function(iv){
        clearInterval(this.timeout);
        this.start(false, iv);
    }
};

用法:

timer.start(function(){
    console.debug('go');
}, 2000);

timer.set_interval(500);

timer.stop();