Screenshot button of frame

In my online html5 canvas game I want the user to be able to download the score of the game as an image. In the forum I've found a script that works very good!

_this.DownloadReset.SaveImage.on('click', function(){
var aTag = document.createElement('a');

aTag.setAttribute('href', canvas.toDataURL("image/png"));

aTag.innerHTML = "Download";

aTag.download = "This_is_your_story.png";

document.body.appendChild(aTag);
});

But I actually want the user to download it with a button within my interface. This shows a download text outside of the div. Is there a easy fix for that? Instance name of my button is "SaveImage".