ImageInfo: reading image metadata (EXIF) with JavaScript

Jacob Seidelin finishes up his binary meme with a post on reading image metadata with JavaScript via a library that groks EXIF data.

It tries to detect the format of the image file and then reads the header and pulls out information about dimensions and color depth among other things. If the EXIF data library is included, it will also gather any EXIF tags from JPEG files.

// URL of the image (must be on the same domain!)
var file = "prettypicture.jpg";
// define your own callback function
function mycallback() {
// either call the ImageInfo.getAllFields([file]) function which returns an object holding all the info
alert(
"All info about this file: " + ImageInfo.getAllFields(file).toSource()
);
// or call ImageInfo.getField([file], [field]) to get a specific field
alert(
"Format: " + ImageInfo.getField(file, "format") + ", dimensions : " + ImageInfo.getField(file, "width") + "x" + ImageInfo.getField(file, "height")
);
}
// finally, load the data
ImageInfo.loadInfo(file, mycallback);