Video.js在Domready上获得自动海报

Question

我有javascript代码来获取HTML5视频缩略图，我可以在点击按钮时获取视频缩略图，我希望使用currentTime属性获取此缩略图，我需要视频的缩略图一段时间，如视频的10秒，20秒和/或1秒

JavaScript的：

<script type="text/javascript">

(function() {
    "use strict";

    var video, $output;
    var scale = 0.25;

    var initialize = function() {
        $output = $("#output");
        video = $("#video").get(0);
        $("#capture").click(captureImage);                
    };

    var captureImage = function() {

        var canvas = document.createElement("canvas");
        canvas.width = video.videoWidth * scale;
        canvas.height = video.videoHeight * scale;
        canvas.getContext('2d')
              .drawImage(video, 0, 0, canvas.width, canvas.height);

        var img = document.createElement("img");
        img.src = canvas.toDataURL();
        $output.prepend(img);
    };

    $(initialize);            

}());
</script>

HTML：

<video id="video" controls="controls">
    <source src="uploads/post_videos/4d2fba78d9fcd7f59567e459c9b65404_131902_popcorntest.mp4" />
</video>

<button id="capture">Capture</button>
<div id="output"></div>