HTMLSelectElement: selectedOptions prope

An HTMLCollection which lists every currently selected HTMLOptionElement which is either a child of the HTMLSelectElement or of an HTMLOptGroupElement within the <select> element.

In other words, any option contained within the <select> element may be part of the results, but option groups are not included in the list.

If no options are currently selected, the collection is empty and returns a length of 0.

In this example, a <select> element with a number of options is used to let the user order various food items.

The HTML that creates the selection box and the <option> elements representing each of the food choices looks like this:

html

<label for="foods">What do you want to eat?</label><br />
<select id="foods" name="foods" size="7" multiple>
  <option value="1">Burrito</option>
  <option value="2">Cheeseburger</option>
  <option value="3">Double Bacon Burger Supreme</option>
  <option value="4">Pepperoni Pizza</option>
  <option value="5">Taco</option>
</select>
<br />
<button name="order" id="order">Order Now</button>
<p id="output"></p>

The <select> element is set to allow multiple items to be selected, and it is 7 rows tall. Note also the <button>, whose role it is to trigger fetching the HTMLCollection of selected elements using the selected property.

The JavaScript code that establishes the event handler for the button, as well as the event handler itself, looks like this:

let orderButton = document.getElementById("order");
let itemList = document.getElementById("foods");
let outputBox = document.getElementById("output");

orderButton.addEventListener("click", () => {
  let collection = itemList.selectedOptions;
  let output = "";

  for (let i = 0; i < collection.length; i++) {
    if (output === "") {
      output = "Your order for the following items has been placed: ";
    }
    output += collection[i].label;

    if (i === collection.length - 2 && collection.length < 3) {
      output += " and ";
    } else if (i < collection.length - 2) {
      output += ", ";
    } else if (i === collection.length - 2) {
      output += ", and ";
    }
  }

  if (output === "") {
    output = "You didn't order anything!";
  }

  outputBox.textContent = output;
});

This script sets up a click event listener on the "Order Now" button. When clicked, the event handler fetches the list of selected options using selectedOptions, then iterates over the options in the list. A string is constructed to list the ordered items, with logic to build the list using proper English grammar rules (including a serial comma).

The resulting content looks like this in action:

HTMLSelectElement: selectedOptions property - Web APIs | MDN