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

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。

其他回答

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。

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(){};
} 

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>
function Sound(url, vol, autoplay, loop)
{
    var that = this;

    that.url = (url === undefined) ? "" : url;
    that.vol = (vol === undefined) ? 1.0 : vol;
    that.autoplay = (autoplay === undefined) ? true : autoplay;
    that.loop = (loop === undefined) ? false : loop;
    that.sample = null;

    if(that.url !== "")
    {
        that.sync = function(){
            that.sample.volume = that.vol;
            that.sample.loop = that.loop;
            that.sample.autoplay = that.autoplay;
            setTimeout(function(){ that.sync(); }, 60);
        };

        that.sample = document.createElement("audio");
        that.sample.src = that.url;
        that.sync();

        that.play = function(){
            if(that.sample)
            {
                that.sample.play();
            }
        };

        that.pause = function(){
            if(that.sample)
            {
                that.sample.pause();
            }
        };
    }
}

var test = new Sound("http://mad-hatter.fr/Assets/projects/FreedomWings/Assets/musiques/freedomwings.mp3");
test.play();

http://jsfiddle.net/sv9j638j/

/*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。