AJAX Image Uploader: Resize or crop images before uploading via AJAX

This class can resize or crop images before uploading via AJAX.

It can listen to changes in form file input so it can detect when the user has chosen an image to upload.

The object creates a canvas element and loads the image and resizes or crops it to given size or position, so it can display a preview of the image within a given page element.

It can also initiate the upload of the image to a given URL using an AJAX request.

The progress, the completion or any errors during the image file upload can be tracked using given callback functions.