Upload and file and convert it into a base64 data url

UCB64URL.js

function uploadAndConvertToBase64DataURL(callback) {
  if (!document.getElementById("B64DURL_UL")) {
    var input = document.createElement("input");
    input.id = "B64DURL_UL";
    input.style.display = "none";
    input.type = "file";
    document.body.appendChild(input);
  }
  var input = document.getElementById("B64DURL_UL");
  input.addEventListener("change", function (e){
    var file = e.target.files[0];
    var reader = new FileReader();
    reader.onload = function (e) {
      callback(e.target.result);
    };
    reader.readAsDataURL(file);
  }, false);
  input.click();
}

// uploadAndConvertToBase64DataURL(function(dataURL){...})