如何在单击贝宝智能按钮上检查表单验证？

Question

我需要点击Paypal智能按钮来验证表单。下面的代码对我不起作用。

paypal.Buttons({

    // onInit is called when the button first renders
    onInit: function(data, actions) {

      // Disable the buttons
      actions.disable();

      // Listen for changes to the checkbox
      document.querySelector('#check')
        .addEventListener('change', function(event) {

          // Enable or disable the button when it is checked or unchecked
          if (event.target.checked) {
            actions.enable();
          } else {
            actions.disable();
          }
        });
    },

    // onClick is called when the button is clicked
    onClick: function() {

      // Show a validation error if the checkbox is not checked
      if (!document.querySelector('#check').checked) {
        document.querySelector('#error').classList.remove('hidden');
      }
    }

  }).render('#paypal-button-container');