想要做一个相册之类的功能，有相框和相片两个图片，现在把这两个图片画入到一个新的canvas，canvas显示出来是正常的 ，但是想把这个canvas转化成新的图片，但是一直转化不了报
Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.
关键的代码是

        var newCanvas = document.createElement('canvas');
        newCanvas.width = 300;
        newCanvas.height = 400;
        newxCtx = newCanvas.getContext("2d");
       var img = new Image();
                img.src = $(".photoWrap_canvas").attr("data-url");
                img.setAttribute("crossOrigin", 'anonymous')
                img.onload = function () {
                    // $(".photoWrap_canvas").hide();
                    newxCtx.drawImage(util.getEl("myCanvas"), 0, 0);
                    newxCtx.drawImage(img, 0, 0, 300, 400);
                    $(".result").prepend(newCanvas);
                   var data = newCanvas.toDataURL('image/jpeg');
                   <span>alert</span>(data)
                   var hc_image = new Image();
                   hc_image.src = data;
                   $(".result").append(hc_image);
                }