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
我用新的音频API写了一个函数来发出哔哔声。
var beep = (function () {
var ctxClass = window.audioContext ||window.AudioContext || window.AudioContext || window.webkitAudioContext
var ctx = new ctxClass();
return function (duration, type, finishedCallback) {
duration = +duration;
// Only 0-4 are valid types.
type = (type % 5) || 0;
if (typeof finishedCallback != "function") {
finishedCallback = function () {};
}
var osc = ctx.createOscillator();
osc.type = type;
//osc.type = "sine";
osc.connect(ctx.destination);
if (osc.noteOn) osc.noteOn(0); // old browsers
if (osc.start) osc.start(); // new browsers
setTimeout(function () {
if (osc.noteOff) osc.noteOff(0); // old browsers
if (osc.stop) osc.stop(); // new browsers
finishedCallback();
}, duration);
};
})();
jsFiddle。
其他回答
以下是我如何使用HTML5让它发出哔哔声: 首先我复制并将windows wav文件转换为mp3，然后我使用以下代码:
var _beep = window.Audio("Content/Custom/Beep.mp3")
function playBeep() { _beep.play()};
全局声明声音文件并在需要时引用它会更快。
<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
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>
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。
我用新的音频API写了一个函数来发出哔哔声。
var beep = (function () {
var ctxClass = window.audioContext ||window.AudioContext || window.AudioContext || window.webkitAudioContext
var ctx = new ctxClass();
return function (duration, type, finishedCallback) {
duration = +duration;
// Only 0-4 are valid types.
type = (type % 5) || 0;
if (typeof finishedCallback != "function") {
finishedCallback = function () {};
}
var osc = ctx.createOscillator();
osc.type = type;
//osc.type = "sine";
osc.connect(ctx.destination);
if (osc.noteOn) osc.noteOn(0); // old browsers
if (osc.start) osc.start(); // new browsers
setTimeout(function () {
if (osc.noteOff) osc.noteOff(0); // old browsers
if (osc.stop) osc.stop(); // new browsers
finishedCallback();
}, duration);
};
})();
jsFiddle。
