document.addEventListener("paste", function (event) {
      var isChrome = false;
      if (event.clipboardData || event.originalEvent) {
        //某些chrome版本使用的是event.originalEvent
        var clipboardData =
          event.clipboardData || event.originalEvent.clipboardData;
        if (clipboardData.items) {
          // for chrome
          var items = clipboardData.items,
            len = items.length,
            blob = null;
          isChrome = true;
          for (var i = 0; i < len; i++) {
            if (items[i].type.indexOf("image") !== -1) {
              //getAsFile() 此方法只是living standard firefox ie11 并不支持
              blob = items[i].getAsFile();
            }
          }
          if (blob !== null) {
            var reader = new FileReader();
            reader.readAsDataURL(blob);
            //base64码显示
            reader.onload = function (event) {
              // event.target.result 即为图片的Base64编码字符串
              var base64_str = event.target.result;
              
            };
            // blob对象
            // var blobUrl = URL.createObjectURL(blob);
            // var fd = new FormData(document.forms[0]);
            // fd.append("the_file", blob, "image.png");
          }
        }
      }
    });