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
/*if you want to beep without using a wave file*/
var context = new AudioContext();
var oscillator = context.createOscillator();
oscillator.type = "sine";
oscillator.frequency.value = 800;
oscillator.connect(context.destination);
oscillator.start();
// Beep for 500 milliseconds
setTimeout(function () {
oscillator.stop();
}, 100);
上面的答案在当时是正确的,但现在是错误的;你可以用纯javascript实现。但是使用javascript的一个答案不再有效,而其他答案非常有限或不使用纯javascript。
我做了我自己的解决方案,工作得很好,让你控制音量,频率和波型。
//if you have another AudioContext class use that one, as some browsers have a limit
var audioCtx = new (window.AudioContext || window.webkitAudioContext || window.audioContext);
//All arguments are optional:
//duration of the tone in milliseconds. Default is 500
//frequency of the tone in hertz. default is 440
//volume of the tone. Default is 1, off is 0.
//type of tone. Possible values are sine, square, sawtooth, triangle, and custom. Default is sine.
//callback to use on end of tone
function beep(duration, frequency, volume, type, callback) {
var oscillator = audioCtx.createOscillator();
var gainNode = audioCtx.createGain();
oscillator.connect(gainNode);
gainNode.connect(audioCtx.destination);
if (volume){gainNode.gain.value = volume;}
if (frequency){oscillator.frequency.value = frequency;}
if (type){oscillator.type = type;}
if (callback){oscillator.onended = callback;}
oscillator.start(audioCtx.currentTime);
oscillator.stop(audioCtx.currentTime + ((duration || 500) / 1000));
};
有人建议我编辑一下,说明它只适用于某些浏览器。然而,据我所知,所有现代浏览器似乎都支持Audiocontext。它在IE上不受支持,但微软已经停产了。如果您在特定的浏览器上有任何问题,请报告。
其他回答
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。
现在用JavaScript AudioContext API就很简单了。主要的桌面和移动网络浏览器完全支持它…
let context = null;
const beep = (freq = 520, duration = 200, vol = 100) => {
const oscillator = context.createOscillator();
const gain = context.createGain();
oscillator.connect(gain);
oscillator.frequency.value = freq;
oscillator.type = "square";
gain.connect(context.destination);
gain.gain.value = vol * 0.01;
oscillator.start(context.currentTime);
oscillator.stop(context.currentTime + duration * 0.001);
}
document.querySelector('button').addEventListener('click', function () {
context = new AudioContext();
beep();
});
我写了一个小应用程序,可以播放马里奥游戏中的音乐,不需要任何音频文件,只有运行时。在我看来,这很有趣,你可以看到源代码并听它。
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>
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(){};
}