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oscillator2.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0"/>
<meta name="format-detection" content="telephone=no"/>
<title>振荡器测试（各种波形）</title>
</head>
<body>
<h1>振荡器测试（Oscillator）各种波形</h1>
<p><strong>按住</strong>按钮以试听音色。</p>
<p>
<input type="button" id="sound_square" name="sound_square" value="方形波(square)"/>
<input type="button" id="sound_triangle" name="sound_triangle" value="三角波(triangle)"/>
<input type="button" id="sound_sine" name="sound_sine" value="正弦波(sine)"/>
<input type="button" id="sound_sawtooth" name="sound_sawtooth" value="锯齿波(sawtooth)"/>
</p>
<fieldset>
<legend>频率</legend>
<div><input type="radio" name="sound" id="sound220hz" /><label for="sound220hz">220 Hz</label></div>
<div><input type="radio" name="sound" id="sound440hz" /><label for="sound440hz">440 Hz</label></div>
<div><input type="radio" name="sound" id="sound880hz" checked /><label for="sound880hz">880 Hz</label></div>
<div><input type="radio" name="sound" id="sound1760hz" /><label for="sound1760hz">1760 Hz</label></div>
<div><input type="radio" name="sound" id="sound3520hz" /><label for="sound3520hz">3520 Hz</label></div>
</fieldset>
<script type="text/javascript">
(function () {
var frequency = 880.0;
var Ctx = window.webkitAudioContext ? window.webkitAudioContext : window.AudioContext;
if (!Ctx) return;
var ctx = new Ctx();
if (!ctx.createOscillator) return;
var dom, oscillator;
function playSound(type) {
if (oscillator) {
oscillator.stop(ctx.currentTime);
}
oscillator = ctx.createOscillator();
oscillator.type = type;
oscillator.frequency.value = frequency;
oscillator.connect(ctx.destination);
oscillator.start(ctx.currentTime);
}
dom = document.getElementById('sound_square');
dom.onmousedown = dom.ontouchstart = function () {
playSound('square');
};
dom = document.getElementById('sound_triangle');
dom.onmousedown = dom.ontouchstart = function () {
playSound('triangle');
};
dom = document.getElementById('sound_sine');
dom.onmousedown = dom.ontouchstart = function () {
playSound('sine');
};
dom = document.getElementById('sound_sawtooth');
dom.onmousedown = dom.ontouchstart = function () {
playSound('sawtooth');
};
document.onmouseup = document.ontouchend = function () {
if (oscillator) {
oscillator.stop(ctx.currentTime);
oscillator = null;
}
};
document.getElementById('sound220hz').onclick = function () {
frequency = 220.0;
};
document.getElementById('sound440hz').onclick = function () {
frequency = 440.0;
};
document.getElementById('sound880hz').onclick = function () {
frequency = 880.0;
};
document.getElementById('sound1760hz').onclick = function () {
frequency = 1760.0;
};
document.getElementById('sound3520hz').onclick = function () {
frequency = 3520.0;
};
})();
</script>
</body>
</html>