To solve the Uncaught Security Exception, you need to add the crossorigin attribute:
<img id = "myid" crossorigin = "anonymous" src="https://www.tutorialspoint.com/images/seaborn-4.jpg?v=2">
function getBase64() {
var myImg = document.getElementById("myid");
var c = document.createElement("canvas");
c.width = myImg.width;
c.height = myImg.width;
var context = c.getContext("2d");
context.drawImage(img, 0, 0);
var dataURL = c.toDataURL("image/png");
alert(dataURL.replace(/^data:image\/(png|jpg);base64,/, ""));
}
getBase64();