js+HTML5实现视频截图的方法

<video id="video" controls="controls">  <source src=".mp4" /></video><button id="capture">Capture</button><div id="output"></div>

(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);      }());