If you will use FileSaver.js it will download on Edge. For using FileSaver.js you need to convert base64 data into the blob data. To do that, please check this post on StackOverflow
Here is an updated fiddle
You need to include FileSaver.js into your project, and your save button will have the following code:
$("#canvas2png").click(function(){
canvas.isDrawingMode = false;
if(!window.localStorage){alert("This function is not supported by your browser."); return;}
var blob = new Blob([b64toBlob(canvas.toDataURL('png').replace(/^data:image\/(png|jpg);base64,/, ""),"image/png")], {type: "image/png"});
saveAs(blob, "testfile1.png");
});
Alternative, quick and dirt solution is to write html data into new tab, and right click on the image and save it. This solution is not required any plugins or libraries.
Your save will simply change to:
$("#canvas2png").click(function(){
canvas.isDrawingMode = false;
if(!window.localStorage){alert("This function is not supported by your browser."); return;}
var html="<img src='"+canvas.toDataURL()+"' alt='canvas image'/>";
var newTab=window.open();
newTab.document.write(html);
});