validating form before paypal simple checkout

Question

I have a simple payment form on my website with an option to pay with paypal express checkout. The rest of my form is validated with jquery validation.

How can I set it up when you click the paypal button, it should validate the form before allowing the paypal popup to open?

$("#form1").validate();

I have a simple paypal render script

<script>
    paypal.Button.render({ ...

On the paypal documentation they offer something like this, but I don't know how to combine the 2

 validate: function(actions) {
       .....
    },

Answer 1

the PayPal new API allows to validate a form that way There is no need to use the onInit func):

paypal
  .Buttons({
    // Run when the user click on the paypal button
    onClick: function(data, actions) {
      // My validation...
      url = searchInput.value
      // My validation Function...
      const isURL = validURL(url)
      if (isURL) {

        // Remove Existing Error message
        if (searchError.classList[2]) {
          searchError.classList.remove('err-message--show')
        }    
        // Enable The Paypal Button
        return true
      } else {
        // Add Error messages
        searchError.classList.add('err-message--show')
        // The paypak wont continue to the paypal page...
        return false
      }
    },
    createOrder: function(data, actions) {
      return actions.order.create({
        purchase_units: [
          {
            amount: {
              value: price,
              currency_code: 'ILS'
            }
          }
        ]
      })
    }
  .render('#paypal-button-container')

There also onApproval and onError functions... (handle the result of the PayPal process...)

Hope I helped, Naveh

Answer 2

There's a full example here:

https://developer.paypal.com/demo/checkout/#/pattern/validation

In the validate() function you need to listen for the form changing and enable/disable the button.