Dynamic form select with JavaScript

Question

I have two categories in my database table.

Women Fashion and Men fashion

Under Men Fashion, I have Men Shoes

Under Women fashion, I have Female bag

I want to a javascript I will use in HTML Form select so that when one selects Women Fashion, he/she will see list of items under women fashion like women bag in the second form or when one select Man Fashion, he/she will see list of items under Men fashion like Men shoe in the second form as well.

sample

<form class="form">
  <div class="form-group">
    <select id="box1" name="num">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
    </select>

    <select id="box2" name="letters">
      <option value="a">A</option>
      <option value="b">B</option>
    </select>
  </div>
</form>

then I have this

$("#box1").on('change', function () {
  var value = $(this).val();

  if (value === "1" || value === "2") {
      $("#box2").show();
  } else {
      $("#box2").hide();
  }
});

but don't know how to implement it using the database value

Please help

Answer 1

APPLY DRY PHILOSOPHY FOR THIS CODE

It's just a test but is it that behavior you're looking for?

HTML CODE

    <form class="form">
  <div class="form-group">
    <select id="collections" name="collection">
      <option>Select a value</option>
      <option value="man">Man</option>
      <option value="woman">Woman</option>
    </select>

    <select id="box2" name="collections-items">
    </select>
  </div>
</form>

JS CODE

let chooseCollections = document.querySelector('#collections')
let selectItems = document.querySelector('#box2')

let manCollection = {
  categories: ["Shoes", "Shirt"]
}

let womanCollection = {
  categories: ["Dress", "Shirt"]
}

chooseCollections.addEventListener('change', (e) => {
  selectItems.querySelectorAll('*').forEach(el => el.remove());
  selectItems.style.display = "none"

  if(e.target.value === "man") {
    selectItems.style.display = "block"
    for(let i = 0; i < manCollection.categories.length; i++) {
      var option = document.createElement('option')
      var value = manCollection.categories[i]
      option.value = value
      option.innerHTML = value
      selectItems.appendChild(option)
    }
  }

  if(e.target.value === "woman") {
    selectItems.style.display = "block"
    for(let i = 0; i < womanCollection.categories.length; i++) {
      var option = document.createElement('option')
      var value = womanCollection.categories[i]
      option.value = value
      option.innerHTML = value
      selectItems.appendChild(option)
    }
  }
})

CSS

#box2 {
  display: none;
}

I've represent manCollection and womanCollection like the data you have in your database. This code is not optimized and can be more efficient but you can start with that.

https://jsfiddle.net/0aek49fr/1/