//= require govuk/multivariate-test

/*jslint browser: true,
 *  indent: 2,
 *  white: true
 */
/*global $, GOVUK */
$(function () {

  GOVUK.taxDiscBetaPrimary = function () {
    $('.primary-apply').html($('#beta-primary').html());
    $('.secondary-apply').html($('#dvla-secondary').html());
  };

  if(window.location.href.indexOf("/tax-disc") > -1) {
    new GOVUK.MultivariateTest({
      name: 'tax-disc-50-50',
      customVarIndex: 20,
      cohorts: {
        tax_disc_beta_control: { callback: function () { } },
        tax_disc_beta: { callback: GOVUK.taxDiscBetaPrimary }
      }
    });
  }
});

@@ -408,13 +408,12 @@
 isc-
-50-50
+beta
 ',%0A 
@@ -486,16 +486,28 @@
 ntrol: %7B
+ weight: 50,
  callbac
@@ -527,16 +527,22 @@
 ) %7B %7D %7D,
+ //50%25
 %0A       
@@ -558,16 +558,28 @@
 _beta: %7B
+ weight: 50,
  callbac
@@ -607,16 +607,22 @@
 rimary %7D
+ //50%25
 %0A      %7D

Set the weights for each cohort