Using HTML5 File API to upload Photos via Facebook Graph API

I'm trying to make a photo organizing Facebook application without using server-side process.

Now I can preview photos by using FileReader object's readAsDataURL method, such as...

var file = e.dataTransfer.files[0];
var reader = new FileReader();
reader.onload = function(e) {
        var imgObj = $(document.createElement('img')).attr('src',reader.result).appendTo('#image_preview_wrapper');
    };
    reader.readAsDataURL(file);
}, false);

The question is how to post the image data to Facebook. I'm trying to do something like

var reader = new FileReader();
reader.onload = function(e) {
    var data = reader.result;
    FB.api('/me/photos','post',{ image : data },funct开发者_如何学运维ion(res){
        alert(res);
    });
}
reader.readAsBinaryString(file);

In this case, I can't set enctype="multipart/form-data" and I'm getting 400 Bad Request.

Can anybody help me?