js 将图片转为base64格式

<img id="image" src='../../assets/xhs.jpeg'>

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getimgBase64 (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 dataURL = canvas.toDataURL("image/jpeg");
      canvas = null; //释放
      dataURL = dataURL.replace("data:image/jpeg;base64,", "");
      return dataURL;
    },
getresult () {
      let _ = this
      var image = document.getElementById('image');
      image.onload = function () {
        var base64img = _.getimgBase64(image);    //base64编码
        console.log("base64img", base64img);
      }
    },
getresult ()