I am using html2canvas to convert HTML to an image.

html2canvas(document.querySelector('body')).then((canvas) => {
    let jpegUrl = canvas.toDataURL('image/jpeg');
    let pngUrl = canvas.toDataURL(); // PNG is the default
    let base64 = canvas.toDataURL('image/jpeg').split(';base64,')[1];
});

My goal is to "when a user submits a form, then capture the current page and convert it to canvas (image)" So that I can store that image in a MySQL database in blob format.
Currently, I am able to convert captured image in base64 string. But then I need to convert base64 string into blob (binary). So that I am able to store blob in MySQL.
How can I do that ?