converting canvas to blob using cropper js

Question

I have created an application using cropper.js for cropping an images. The application is working and the image is cropping, after that I am trying to send the cropped image as blob to the server side for storing,

As per the cropper.js documentation we can use canvas.toDataURL to get a Data URL, or use canvas.toBlob to get a blob and upload it to server with FormData. when I tried canvas.toDataURL() I am getting the base64 string, but actually I need to send the file as blob so I tried with canvas.toBlob() but I am getting Uncaught TypeError: canvas.toBlob is not a function in chrome and TypeError: Not enough arguments to HTMLCanvasElement.toBlob. in Firefox

Can anyone please tell me some solution for this

My code is like this

var canvas = $image.cropper("getCroppedCanvas", undefined);
var formData = new FormData();
formData.append('mainImage', $("#inputImage")[0].files[0]);
formData.append('croppedImage', canvas.toBlob());