2 input fields that aren't required but both must be filled?

Question

I have 2 input fields:

<div class="row">
    <div class="col-1-2"><input type="text" placeholder="Item 1" name="custom_item_1" id="custom-item-1"></div>
    <div class="col-1-2"><input type="number" placeholder="Amount 1" name="custom_amount_1" id="custom-amount-1"></div>
</div>

They are not required, but if there is data in one then I need them both to be filled out...

Would the best way to do this to add a required to the end of both of the inputs when one is being filled out?

Keep in mind I'm already using JS to dynamically add more row's like that, with Item/Amount 2, 3, 4, etc...

I'm not sure how to go about this.

---

I would think the workflow would go like this:

1) upon being filled, find ID's of 'item' and 'amount' - eg... custom-item-1 and custom-amount-1

2) add 'required' to the inputs with the id's

---

Here's the code that I'm using to dynamically add row's incase it's useful:

  // add custom fields - add fields upon pressing button
  var iCustom = 2; // starts at 2 because 1 is already present
  function addCustomFields() {
    var newRow = document.createElement('div');
    newRow.className = 'row';
    newRow.innerHTML = '<div class="col-1-2"><input type="text" placeholder="Item ' + iCustom + '" name="custom_item_' + iCustom + '" id="custom-item-' + iCustom + '"></div><div class="col-1-2"><input type="number" placeholder="Amount ' + iCustom + '" name="custom_amount_' + iCustom + '" id="custom-amount-' + iCustom + '"></div>';
    document.getElementById('section-add-custom-fields').appendChild(newRow);
    iCustom++;
  }
  document.getElementById('add-custom-fields').addEventListener('click', addCustomFields);

---

EDIT:

Final code:

  // requires both inputs to be filled
  document.getElementById('form-button-submit').addEventListener('click', function() {
    for (var i = 1; !!document.getElementById("custom-item-"+i); i++) {
    var itemEntered = !!document.getElementById("custom-item-"+i).value,
        amountEntered = !!document.getElementById("custom-amount-"+i).value;
      if(itemEntered != amountEntered) {
        document.getElementById("custom-item-"+i).required = true
        document.getElementById("custom-amount-"+i).required = true
      }
    }
  });

  <button type="submit" id="form-button-submit">Continue</button>

Answer 1

I'd just put this validation code in the event listener of whatever submit button you have:

for(var i = 1; !!document.getElementById("custom-item-"+i); i++) {
    var itemEntered = !!document.getElementById("custom-item-"+i).value,
        amountEntered = !!document.getElementById("custom-amount-"+i).value;
    if(itemEntered != amountEntered) {

            // One was entered, but both weren't filled out
            // so handle that situation accordingly
    }
}

A bit of explanation: !! turns stuff into boolean values . Therefore, the for loop essentially loops over all of your "custom item" fields until it finds one that doesn't exist.

Some options for what you can do to handle the error case in the if statement:

• Add an error message next to the fields
• Disable the submit button (although this might be questionable user-interface design)
• Somehow prevent the actual submission code from running