jQuery validate across multiple fields

Question

I have 3 input fields that ask for the number of people, and of them how many are adults and how many are children. I am trying to use jQuery validate plugin to add a custom

Answer 1

As suggested in comments this is not a good practice. Nonetheless, if you still want to do it:

$("#form2").validate({
    errorElement: "span",
        rules: {
        attendees: {
             equal: $("#form2 #adults").val() + $("#form2 #children").val();
        },              
        adults: {
             required: true,
             digits: true
        },              
        children: {
             required: true,
             digits: true
        }
    },
    messages: {
        attendees: "Enter the number of persons (including yourself)", 
        adults: "Enter number of adults", 
        children: "Enter number of childern"                
    }               
});