图片转base64 用canvas.toDataURL()

function getBase64Image(img) {
    var canvas = document.createElement("canvas");
    canvas.width = img.width;
    canvas.height = img.height;
    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0, img.width, img.height);
    var ext = img.src.substring(img.src.lastIndexOf(".")+1).toLowerCase();
    return canvas.toDataURL();
}
var img = imgurl ;//imgurl 就是你的图片路径
var image = new Image();
image.setAttribute("crossOrigin",'Anonymous');
//解决 canvas 将图片转为base64报错: Uncaught DOMException: Failed to execute 'toDataURL' on //'HTMLCanvasElement'
image.src = img;
image.onload = function(){
                    saveImgBase64 = getBase64Image(image);
                }