How to save a file created with js + canvas to mp4?

Question

JavaScript

How to create a video file and attach it there on the alpha channel, for example, I found the text as a whole .

EXAMPLE
3 layers = video + plate + text (we change the text simply in the HTML text field, select from several plates and all this is superimposed on the video file)

But then, how to download the created file assembled using js and canvas in mp4 format to a computer? Didn't find any info anywhere. Maybe you know where to dig?

Answer 1

First line on Google: stackoverflow.com/questions/13405129/javascript-cr...

function saveAs(blob, file) {
   if (navigator.msSaveBlob) {
      navigator.msSaveBlob(blob, file);
   } else {
    var a = docuemnt.createElement("a");
    a.href = URL.createObjectURL(blob);
    a.download = file;
    a.click();
   }
}

Answer 2

it is forbidden