当我在将视频上传到服务器之前尝试获取屏幕截图并将其另存为PNG时,我遇到了以下问题

我希望你能解决我的问题......
/*Output image show view*/
$('#file_browse').change(function(e){
getVideo(this);
});
var capbtn = document.querySelector('#video_capture');
var video = document.querySelector('video');
var canvas = document.querySelector('canvas');
var context = canvas.getContext('2d');
var w, h, ratio;
video.addEventListener('loadedmetadata', function() {
ratio = video.videoWidth / video.videoHeight;
w = video.videoWidth - 100;
h = parseInt(w / ratio, 10);
canvas.width = w;
canvas.height = h;
}, false);
capbtn.addEventListener("click", function(){
context.fillRect(0, 0, w, h);
context.drawImage(video, 0, 0, w, h);
var objImageData = canvas.toDataURL("data:image/png;");
});
function getVideo(input) {
if (input.files && input.files[0]) { …Run Code Online (Sandbox Code Playgroud) <!doctype html>
<canvas id="canvas" height="200" width="200"></canvas>
<div id="new"></div>
<script>
var div = document.getElementById("new");
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var img = new Image();
img.src = 'http://www.w3.org/html/logo/downloads/HTML5_Logo_512.png';
//img.src = 'local.png';
img.onload = function(){
//draws the image on the canvas (works)
ctx.drawImage(img,0,0,200,200);
//creates an image from the canvas (works only for local.png)
var sourceStr = canvas.toDataURL();
//creates the img-tag and adds it to the div-container
var newImage = document.createElement("img");
newImage.src = sourceStr;
div.appendChild(newImage);
}
</script>
Run Code Online (Sandbox Code Playgroud)
此脚本使用html5徽标创建画布.从这个画布我想使用"toDataURL()" - 方法创建一个图像.在这里我收到一个安全错误.
Firefox说 …