Generate an image of a div and Save as

Here is the final code, if it can helps you :

function PrintDiv(div)
{
    html2canvas((div), {
        onrendered: function(canvas) {
            var myImage = canvas.toDataURL();
            downloadURI(myImage, "MaSimulation.png");
      }
    });
}

function downloadURI(uri, name) {
    var link = document.createElement("a");

    link.download = name;
    link.href = uri;
    document.body.appendChild(link);
    link.click();   
    //after creating link you should delete dynamic link
    //clearDynamicLink(link); 
}

This works fine for me.

function downloadURI(uri, name) {
    var link = document.createElement("a");

    link.download = name;
    link.href = uri;
    document.body.appendChild(link);
    link.click();
    clearDynamicLink(link); 
}

function DownloadAsImage() {
    var element = $("#table-card")[0];
    html2canvas(element).then(function (canvas) {
        var myImage = canvas.toDataURL();
        downloadURI(myImage, "cartao-virtual.png");
    });
}

Have you looked at

http://eligrey.com/demos/FileSaver.js/

Looks like it does what you need

You could do this approach:

//Creating dynamic link that automatically click
function downloadURI(uri, name) {
    var link = document.createElement("a");
    link.download = name;
    link.href = uri;
    link.click();
    //after creating link you should delete dynamic link
    //clearDynamicLink(link); 
}

//Your modified code.
function printToFile(div) {
    html2canvas(div, {
        onrendered: function (canvas) {
            var myImage = canvas.toDataURL("image/png");
            //create your own dialog with warning before saving file
            //beforeDownloadReadMessage();
            //Then download file
            downloadURI("data:" + myImage, "yourImage.png");
        }
    });
}