methods:{
    base64ToBlob(urlData) {
      var arr = urlData.split(',');
      var mime = arr[0].match(/:(.*?);/)[1] || 'image/png';
      // 去掉url的頭，並轉化為byte
      var bytes = window.atob(arr[1]);
      // 處理異常,將ascii碼小於0的轉換為大於0
      var ab = new ArrayBuffer(bytes.length);
      // 生成檢視（直接針對記憶體）：8位無符號整數，長度1個位元組
      var
 
 ia = new Uint8Array(ab);

      for (var i = 0; i < bytes.length; i++) {
          ia[i] = bytes.charCodeAt(i);
      }

      return new Blob([ab], {
          type: mime
      });
  },
  getImgUrl(){
    let that = this;
    html2canvas(document.querySelector("#exitImg"),opts).then(canvas =>
 
 {
         console.log(canvas)
         var dataUrl = canvas.toDataURL();
         let fileImg = that.base64ToBlob(dataUrl)
         var fd = new FormData()
         fd.append('file', fileImg,"image.jpg")
         let config = {
             headers: {
                 'Content-Type': 'multipart/form-data'
 

             }
         }
         axios.post(that.uploadUrl, fd,config).then( res => {
             console.log(res)
         }).catch( res => {
             console.log(res)
         })
     });    
  }
},
mounted:function(){
    this.getImgUrl()
}