_donate_widget_js.html.erb

var handler = StripeCheckout.configure({
  key:         '<%= DC::SECRETS['stripe']['publish'] %>',
  locale:      'auto',
  name:        'DocumentCloud',
  description: 'Donation to DocumentCloud.org',
  image:       '/images/common/dc_logomark_social_square.png',
  billingAddress: true,
  token: function(token) {
    $('#stripe_token').val(token.id);
    $('#stripe_email').val(token.email);
    $('#donation-form').get(0).submit();
  }
});
$(window).on('popstate', function() {
  handler.close();
});

$('#donation-form').on('submit', function(e) {
  e.preventDefault();

  var $form    = $('#donation-form');
  var $error   = $('#error_explanation').html('');

  if (_.isFunction($form.serializeObject)) {
    var formData = $form.serializeObject();
  } else {
    var formData = {
      donation_amount_other: $('#donation-amount-other').val(),
      donation_amount: 0
    };
  }

  var amount = formData.donation_amount_other || formData.donation_amount;
  if (_.isUndefined(amount)) {
    $error.html('<p class="my-2 text-danger">Please enter a valid amount in USD ($).</p>');
    return false;
  }
  amount = amount.replace(/\$/g, '').replace(/\,/g, '')
  amount = parseFloat(amount);
  if (_.isNaN(amount)) {
    $error.html('<p class="my-2 text-danger">Please enter a valid amount in USD ($).</p>');
  }
  else if (amount < 5.00) {
    $error.html('<p class="my-2 text-danger">Donation amount must be at least $5.</p>');
  }
  else {
    amount = Math.floor(amount * 100);
    $('#donation_amount_cents').val(amount);
    handler.open({
      amount: amount
    })
  }
});
$('.donation-page #donation-amount-other').on('keyup', function(){
  var $form    = $('#donation-form');
  var formData = $form.serializeObject();
  if (formData.donation_amount_other) {
    var $checked = $('#donation-form').find('[name="donation_amount"]:checked');
    $checked.prop('checked', false).closest('.active').removeClass('active');
    $(this).addClass('active');
  } else {
    $(this).removeClass('active');
  }
});
$('#donation_amounts .btn').on('click', function(){
  $('#donation-amount-other').val('').removeClass('active');
});