Validation rule - One field is great then another

Question

Is there a code that can validate that one field is greater then another.

I have a mileage start field and a mileage end.

Want to validate the end is entered greater than the start field.

Thanks

fields are mileage_start and mileage_end

teldrive · Accepted Answer

Following examples of Bob, this worked for my
(inside of multifield areas i have insterted one "javascript custom code" with this function

jQuery.fn.form.settings.rules.customfn = function() {
field1=document.getElementById("field1").value;
field2=document.getElementById("field2").value;
let result = (field1 <  field2) ? true:false;
  return result;
};

and in validation rules of field2

customfn: Error message because field2 must be greater than field1

that works fine, thanks Bob