几乎每一个网页是必备图片上传，图片裁剪功能，这里通过cropbox.js插件实现该功能。

<script src="js/jquery-1.11.1.min.js"></script>
<script src="js/cropbox.js"></script>
<script type="text/javascript">
  $(window).load(function() {
    var options =
    {
      thumbBox: '.thumbBox',
      spinner: '.spinner',
      imgSrc: 'images/avatar.png'
    }
    var cropper = $('.imageBox').cropbox(options);
    $('#file').on('change', function(){
      var reader = new FileReader();
      reader.onload = function(e) {
        options.imgSrc = e.target.result;
        cropper = $('.imageBox').cropbox(options);
      }
      reader.readAsDataURL(this.files[0]);
      this.files = [];
    })
    $('#btnCrop').on('click', function(){
      var img = cropper.getDataURL();
      $('.cropped').append('<img src="'+img+'">');
    })
    $('#btnZoomIn').on('click', function(){
      cropper.zoomIn();
    })
    $('#btnZoomOut').on('click', function(){
      cropper.zoomOut();
    })
  });
</script>