我想我的网页哔哔每当用户超过我的<textarea>的最大字符限制。


当前回答

function beep(freq = 660, duration = 90, vol = 50) { var context = new(window.AudioContext || window.webkitAudioContext); const oscillator = context.createOscillator(); const gain = context.createGain(); gain.gain.setValueAtTime(0, context.currentTime); gain.gain.linearRampToValueAtTime(1, context.currentTime + 0.002); oscillator.connect(gain); oscillator.frequency.value = freq; oscillator.type = "square"; gain.connect(context.destination); oscillator.start(context.currentTime); oscillator.stop(context.currentTime + duration * .001); oscillator.onended = () => context.close(); } <br> <center><button onclick="beep()">Beep!</button></center>

其他回答

该代码支持多个哔哔声的排序,以及频率的逐渐变化('ramp'标志)。下面给出了两个例子。

<script>
var audioContext = null;
var oscillatorNode = null;
var stopTime = 0;

function beep (frequency, durationSec, ramp=false)
{
    if (oscillatorNode == null) {
        audioContext = new (window.AudioContext || window.webkitAudioContext) ();
        stopTime = audioContext.currentTime;

        oscillatorNode = audioContext.createOscillator();
        oscillatorNode.type = "sine";
        oscillatorNode.connect (audioContext.destination);
        if (ramp) {
            oscillatorNode.frequency.setValueAtTime (frequency, stopTime);
        }
        oscillatorNode.start ();
        oscillatorNode.onended = function() {
            oscillatorNode = null;
            audioContext = null;
        }
    }

    if (ramp) {
        oscillatorNode.frequency.linearRampToValueAtTime (frequency, stopTime); // value in hertz
    } else {
        oscillatorNode.frequency.setValueAtTime (frequency, stopTime);  // value in hertz
    }

    stopTime += durationSec;
    oscillatorNode.stop (stopTime);
}
function test1()
{
        beep (250, 0.5);
        beep (1000, 0.2);
        beep (550, 0.5);
}
    
function test2()
{
        beep (50, 2, true);
        beep (5000, 2, true);
        beep (50, 0, true);
}
</script>
    
<button onclick='test1()'>Beep!</button>
<button onclick='test2()'>Beep(ramped)!</button>

当我们读到这个答案时,HTML5将为你解决这个问题,如果你愿意这样做的话。所有现代浏览器都支持HTML5音频。

下面是示例的副本:

var snd = new Audio("file.wav"); // buffers automatically when created
snd.play();
function Sound(url, vol, autoplay, loop)
{
    var that = this;

    that.url = (url === undefined) ? "" : url;
    that.vol = (vol === undefined) ? 1.0 : vol;
    that.autoplay = (autoplay === undefined) ? true : autoplay;
    that.loop = (loop === undefined) ? false : loop;
    that.sample = null;

    if(that.url !== "")
    {
        that.sync = function(){
            that.sample.volume = that.vol;
            that.sample.loop = that.loop;
            that.sample.autoplay = that.autoplay;
            setTimeout(function(){ that.sync(); }, 60);
        };

        that.sample = document.createElement("audio");
        that.sample.src = that.url;
        that.sync();

        that.play = function(){
            if(that.sample)
            {
                that.sample.play();
            }
        };

        that.pause = function(){
            if(that.sample)
            {
                that.sample.pause();
            }
        };
    }
}

var test = new Sound("http://mad-hatter.fr/Assets/projects/FreedomWings/Assets/musiques/freedomwings.mp3");
test.play();

http://jsfiddle.net/sv9j638j/

没有跨浏览器的方法来实现这纯javascript。相反,您可以使用一个小的.wav文件,使用嵌入或对象标记播放。

这在JavaScript中是不可能直接实现的。您需要在HTML中嵌入一个简短的WAV文件,然后通过代码播放该文件。

一个例子:

<script>
function PlaySound(soundObj) {
  var sound = document.getElementById(soundObj);
  sound.Play();
}
</script>

<embed src="success.wav" autostart="false" width="0" height="0" id="sound1"
enablejavascript="true">

然后从JavaScript代码中调用它,如下所示:

PlaySound("sound1");

这应该完全是你想要的-你只需要自己找到/创建哔哔声,这应该是微不足道的。