console 命令行工具 X clear

console

var btn = document.getElementById('choose'),
show = document.getElementById('show');

btn.onchange = function() {
  var reader = new FileReader();
  reader.readAsDataURL(this.files[0]);
  console.log(this.files[0]);
  reader.onload = function(e) {
    show.src = e.target.result;
  }
}

<input type="file" id="choose" value="选择文件">
<img id="show" />