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

<html>
<head>
    <script src='https://surikov.github.io/webaudiofont/npm/dist/WebAudioFontPlayer.js'></script>
    <script src='https://surikov.github.io/webaudiofontdata/sound/0000_JCLive_sf2_file.js'></script>
    <script>
        var selectedPreset=_tone_0000_JCLive_sf2_file;
        var AudioContextFunc = window.AudioContext || window.webkitAudioContext;
        var audioContext = new AudioContextFunc();
        var player=new WebAudioFontPlayer();
        player.loader.decodeAfterLoading(audioContext, '_tone_0000_JCLive_sf2_file');
    </script>
</head>
<body>
    <p><a href="#" onmousedown="player.queueWaveTable(audioContext, audioContext.destination, selectedPreset, 0, 55, 3.5);">Play a note</a></p>
    <hr/>
    <p><a href="https://github.com/surikov/webaudiofont">source</a></p>
</body>

听这里 https://jsbin.com/lamidog/1/edit?html,output

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>

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。

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>

您需要从某个地方提供声音文件。以下是来自Scriptaculous的Sound库的代码:

//Default:
<embed style="height:0" id="sound_#{track}_#{id}" src="#{url}" loop="false" autostart="true" hidden="true"/>

//For Gecko:
if(Prototype.Browser.Gecko && navigator.userAgent.indexOf("Win") > 0){
  if(navigator.plugins && $A(navigator.plugins).detect(function(p){ return p.name.indexOf('QuickTime') != -1 }))
    Sound.template = new Template('<object id="sound_#{track}_#{id}" width="0" height="0" type="audio/mpeg" data="#{url}"/>');
  else if(navigator.plugins && $A(navigator.plugins).detect(function(p){ return p.name.indexOf('Windows Media') != -1 }))
    Sound.template = new Template('<object id="sound_#{track}_#{id}" type="application/x-mplayer2" data="#{url}"></object>');
  else if(navigator.plugins && $A(navigator.plugins).detect(function(p){ return p.name.indexOf('RealPlayer') != -1 }))
    Sound.template = new Template('<embed type="audio/x-pn-realaudio-plugin" style="height:0" id="sound_#{track}_#{id}" src="#{url}" loop="false" autostart="true" hidden="true"/>');
  else
    Sound.play = function(){};
} 

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。