Can you tell me more about this form? Is this "Pending" field a drop-down? Does it appear in a table? Would you get this information from a lookup rule?

Here's a sample to help you get started. Add the request CSS class to the field where the "Request Pending" value is. If you're using a checkbox, note that Forms will replace spaces with underscores in these values.

Add the total CSS class to the field where you want the number of pending requests to appear.

$(document).ready(function() {
    $(document).on('change','.request select, .request input', tallyRequests)
  
    function tallyRequests() {
        $('.total input').val(($('.request option[value="Request Pending"]:checked').length) + $('.request input[value="Request_Pending"]:checked').length); 
    }
});