Convert binary data to base64 with JavaScript

Question

HTML5 enable you to store data locally which I think it is great. For example here is how you can use it:

var store = window.localStorage;
store.setItem('foo', "hellow world");
var test = store.getItem('foo');
// test should = "hellow world"

In HTML you can dynamically display an image by setting its source to:

"data:image/jpg;base64," + (base64string)

So my question is how can I convert binary data to a base64 string so that I can take advantage of html5 local storage?

For example it will be great if I could:

$.ajax({
   url: 'someImage.png',
   type: 'POST',
   success: function (r) {
                
      // here I want to convert r to a base64 string !
      // r is not binary so maybe I have to use a different approach
      var data = ConvertToBase64(r);
      document.getElementById("img").src = "data:image/png;base64," + data;

   },
});

---

I know I could solve this problem by wrapping the image around a canvas using html5 then converting that to base64string. also I can make a specific service on the server that will send a base64 string data of that image (someImage.aspx).I just want to know if it will by possible to retrieve binary data from a server and convert that to a base64 string.

Answer 1

Try the btoa function:

   var data = btoa(r);