javascript - 更改类名时 CSS 不会更改

Question

我正在使用 HTML5 媒体 API 并停留在它的静音属性上。我有一个静音按钮，每当我单击它时，我都想用它来静音和取消静音特定视频的音频。问题是每当我将它静音时它都会工作，但我无法取消静音。类和标题值已正确设置为适当的值，但音量或图标图像没有变化。这是我的 jsfiddle 代码的链接 http://jsfiddle.net/7AS3C/1/当我将代码上传到 jsfiddle 时，CSS 问题没有发生。如果有人帮助我解决 javascript 问题，我将不胜感激。

<div id="mediaplayer">
    <video id="media-video" controls>
        <source src='http://video.webmfiles.org/big-buck-bunny_trailer.webm' type='video/webm' controls>
    </video>
    <div>
        <div id="media-controls">
            <progress id="progress-bar" min="0" max="100" value="0"></progress>
            <button id='replay-button' class='replay' title='replay' onclick='replayMedia();'>Replay</button>
            <button id='play-pause-button' class='play' title='play' onclick='togglePlayPause();'>Play</button>
            <button id='stop-button' class='stop' title='stop' onclick='stopPlayer();'>Stop</button>
            <button id='volume-inc-button' class='volume-plus' title='increase volume' onclick='changeVolume("+");'>Increase volume</button>
            <button id='volume-dec-button' class='volume-minus' title='decrease volume' onclick='changeVolume("-");'>Decrease volume</button>
            <button id='mute-btn' class='mute' title='mute' onclick='toggleMute();'>Mute</button>
        </div>
    </div>
</div>

这是CSS

.unmute {
    width:45px;
    height:48px;
    background:url('mute.png');
    background-position: 0px 0px;
}
.mute {
    width:45px;
    height:48px;
    background:url('unmute.png');
    background-position: 0px 0px;
}

这是我的javascript

muteBtn = document.getElementById('mute-btn');

function toggleMute() {
    if (player.muted = false) {
        changeButtonType(muteBtn, 'mute');
        player.muted = "true";
    } else if (player.muted = true) {
        changeButtonType(muteBtn, 'unmute');
        player.muted = "false";

    } else player.muted = "false";
}

function changeButtonType(buttonType, value) {
    buttonType.title = value;
    buttonType.innerHTML = value;
    buttonType.className = value;
}

Answer 1

条件逻辑是赋值而不是比较

if (player.muted = false) {

应该是

if (player.muted === false) {

和

player.muted = "true"; 

应该是

player.muted = true;

同样适用于假 block