How to get base64 encoded data from html image

Question

I have a registration form where users can choose an avatar. They have 2 possibilities:

1. Choose a default avatar
2. Upload their own avatar

Answer 1

You can try following sample http://jsfiddle.net/xKJB8/3/

<img id="preview" src="http://www.gravatar.com/avatar/0e39d18b89822d1d9871e0d1bc839d06?s=128&d=identicon&r=PG">
<canvas id="myCanvas" />

---

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var img = document.getElementById("preview");
ctx.drawImage(img, 10, 10);
alert(c.toDataURL());

Answer 2

You can also use the FileReader class :

    var reader = new FileReader();
    reader.onload = function (e) {
        var data = this.result;
    }
    reader.readAsDataURL( file );