Tainted Canvas -

: The content remains visible to the user, but it cannot be programmatically read back or saved by scripts. Why It Exists

Once a canvas is "tainted," it is no longer considered "origin-clean," and the browser blocks functions that allow you to read its pixel data: Tainted Canvas

: You cannot use toDataURL() , toBlob() , or captureStream() . : The content remains visible to the user,