这是新的 File API 从W3C（Mozilla有很多关系）。我已经做了几个File API示例在其他***问题的答案可能是有用的：

It's the new File API from the W3C (which Mozilla had a lot to do with). I've done a couple of File API examples in answers to other *** questions that may be useful:

• HTML5文件API读为文本和二进制


• 在文件上传期间使用Javascript获取图像尺寸

• HTML5 File API read as text and binary
• Get Image dimensions using Javascript during file upload
• How to know the size of the image to be uploaded with javascript?

第二个，特别是显示将局部图像文件加载到 img 元素中，您可以随时使用 canvas 。

That second one, in particular, shows loading a local image file into an img element, which you could readily use with a canvas.

如果您想要拖放方面，还可以查看HTML5 拖放东西;相关文章： Google转换为HTML5的Gmail新的拖放附件 。

If you want the drag-and-drop aspect, you might also check out the HTML5 Drag and Drop stuff; related article: Google Turns to HTML5 for Gmail’s New Drag-and-Drop Attachments.