HTMLOptionsCollection: add() method

Syntax

add(item)
add(item, before)

Parameters

item

An HTMLOptionElement or HTMLOptGroupElement.

before Optional

An element of the collection, or a numeric 0-based index representing the element that the item should be inserted before. If omitted, null, or the index does not exist, the new element is appended to the end of the collection.

Return value

None (undefined).

Exceptions

HierarchyRequestError DOMException

Thrown if the item passed to the method is an ancestor of the element into which it is to be inserted.

Description

By default, the add() appends the <option> or <optgroup> passed as the parameter to the end of the collection. You can define where the added <option> or <optgroup> should be placed by specifying the before parameter. The before is the <option> element or a numeric 0-based index of the <option> element the added element should precede.

If the before parameter is null or out of range (or omitted), the <option> or <optgroup> will be appended as the last element in the collection, outside of any <optgroup>. If the <option> referenced by the before parameter is in an <optgroup>, an added HTMLOptionElement will be in the same group.

The <optgroup> element can only contain <option> elements as child nodes. The add() method will successfully add an HTMLOptGroupElement to the end of the HTMLOptionsCollection or between <optgroup> elements only. In other words, attempting to add an HTMLOptGroupElement before an <option> within an <optgroup> may silently fail if the <option> referenced by the before parameter is not the first <option> within its <optgroup>.

Examples

const optionList = document.querySelector("select").options;
const firstOption = document.createElement("option");
firstOption.text = "new item";
optionList.add(firstOption, 0); // added as the first item
optionList.add(optionList[0]); // moves the first item to the end

Specifications

Browser compatibility

See also

• <select>
• HTMLOptionsCollection.remove
• HTMLOptionsCollection.length
• HTMLOptionsCollection.selectedIndex