如何通过javascript更改jwplayer配置

<script src="https://content.jwplatform.com/libraries/xxxxxxx.js"></script>

var player = jwplayer('player-container').setup({
    file: 'video.mp4',
    width: '640',
    height: '360'
});

player.setConfig({
    autostart: true
});

player.setConfig({
    volume: 80
});

player.setConfig({
    playbackRateControls: true
});

player.setConfig({
    qualityLabels: {
        '240p': 'http://example.com/video_240p.mp4',
        '480p': 'http://example.com/video_480p.mp4',
        '720p': 'http://example.com/video_720p.mp4'
    }
});

player.setConfig({
    autostart: true,
    volume: 80,
    playbackRateControls: true,
    qualityLabels: {
        '240p': 'http://example.com/video_240p.mp4',
        '480p': 'http://example.com/video_480p.mp4',
        '720p': 'http://example.com/video_720p.mp4'
    }
});