1. function getBase64(file) {
    2.    var reader = new FileReader();
    3.    reader.readAsDataURL(file);
    4.    reader.onload = function () {
    5.      console.log(reader.result);
    6.    };
    7.    reader.onerror = function (error) {
    8.      console.log('Error: ', error);
    9.    };
    10. }
    12. var file = document.querySelector('#files > input[type="file"]').files[0];
    13. getBase64(file); // prints the base64 string