CODE EXAMPLE FOR JAVASCRIPT

upload preview image js

// <input type="file" accept="image/*" id="img-input">
// <img id="preview"/>
function readURL(input) {
      if (input.files && input.files[0]) {
          var reader = new FileReader();
          reader.onload = function(e) {
          $('#preview').attr('src', e.target.result);
          }
          reader.readAsDataURL(input.files[0]);
      } else {
          $('#preview').attr('src', '');
      }
    }

  $("#img-input").change(function() {
    readURL(this);
  });