How can you encode a string to Base64 in JavaScript?

Question

I have a PHP script that can encode a PNG image to a Base64 string.

I\'d like to do the same thing using JavaScript. I know how to open files, but I\'m not sure how

Answer 1

if you need to encode HTML image object, you can write simple function like:

function getBase64Image(img) {  
  var canvas = document.createElement("canvas");  
  canvas.width = img.width;  
  canvas.height = img.height;  
  var ctx = canvas.getContext("2d");  
  ctx.drawImage(img, 0, 0);  
  var dataURL = canvas.toDataURL("image/png");  
  // escape data:image prefix
  return dataURL.replace(/^data:image\/(png|jpg);base64,/, "");  
  // or just return dataURL
  // return dataURL
}  

To get base64 of image by id:

function getBase64ImageById(id){  
  return getBase64Image(document.getElementById(id));  
} 

more here