JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    Name: <input name="atendeename[]">
    Entree: <input name="entree[]"><br>
    Name: <input name="atendeename[]">
    Entree: <input name="entree[]"><br>
    Name: <input name="atendeename[]">
    Entree: <input name="entree[]"><br>
    Name: <input name="atendeename[]">
    Entree: <input name="entree[]"><br>
    Name: <input name="atendeename[]">
    Entree: <input name="entree[]"><br>
    <input type="submit" value="Submit">
</form>

JavaScript

// Prevent form submit if any entrees are missing
$('form').submit(function(e){
    
    e.preventDefault();
    
    // Cycle through each Attendee Name
    $('[name="atendeename[]"]', this).each(function(index, el){
        
        // If there is a value
        if ($(el).val()) {
         
            // Find adjacent entree input
            var entree = $(el).next('input');
           
            // If entree is empty, don't submit form
            if ( ! entree.val()) {
                alert('Please select an entree');
                entree.focus();
                return false;
            }
            
        }
        
    });
    
    $('form').unbind('submit').submit();
    
});