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
<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
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>
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。
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>
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