Q:

jQuery - set one input equal to 5% of another and more 1

I have two input fields - a donation and a tip field.  I need to set the tip field equal to 5% of the donation field when the donation field is changed.  And I need to make sure both fields are never less than $1.
I have this, but it's not working correctly:
$('#donationAmount').change(function() {
    var donationAmount = $('#donationAmount');
    var tipAmount = $('#tipAmount');

    if(parseFloat(tipAmount.val()) <= 1){
        tipAmount.val(1);
    }else{
        tipAmount.val(parseFloat(donationAmount.val()*0.05).toFixed(2));
    }

    if(parseFloat(donationAmount.val()) < 1){
        donationAmount.val(1);
    }
});

A:

The code below should grab the donation amount and if it's below $1.00 set it to $1.00, then calculate the tip at 5% and if it's below $1.00 set it to a $1.00 and repopulate both fields.  I would recommend validating on the back end as well since the field can be changed to arbitrary value in a number of ways.
$('#donationAmount').on('change', function(){ 
  var $donationAmount = $(this);
  var $tipAmount = $('#tipAmount');

  var donation = Number($donationAmount.val());
  var tip;

  donation = (donation >= minimum)? donation:1;
  tip = (donation*0.05 >= minimum)? donation*0.05:1;

  $donationAmount.val( donation.toFixed(2) );
  $tipAmount.val( tip.toFixed(2) );
});

