HTMLElement: change event - Web APIs 编辑

The change event is fired for <input>, <select>, and <textarea> elements when an alteration to the element's value is committed by the user. Unlike the input event, the change event is not necessarily fired for each alteration to an element's value.

Depending on the kind of element being changed and the way the user interacts with the element, the change event fires at a different moment:

• When the element is :checked (by clicking or using the keyboard) for <input type="radio"> and <input type="checkbox">;
• When the user commits the change explicitly (e.g., by selecting a value from a <select>'s dropdown with a mouse click, by selecting a date from a date picker for <input type="date">, by selecting a file in the file picker for <input type="file">, etc.);
• When the element loses focus after its value was changed, but not commited (e.g., after editing the value of <textarea> or <input type="text">).

The HTML specification lists the <input> types that should fire the change event.

Examples

<select> element

HTML

<label>Choose an ice cream flavor:
  <select class="ice-cream" name="ice-cream">
    <option value="">Select One …</option>
    <option value="chocolate">Chocolate</option>
    <option value="sardine">Sardine</option>
    <option value="vanilla">Vanilla</option>
  </select>
</label>

<div class="result"></div>

body {
  display: grid;
  grid-template-areas: "select result";
}

select {
  grid-area: select;
}

.result {
  grid-area: result;
}

JavaScript

const selectElement = document.querySelector('.ice-cream');

selectElement.addEventListener('change', (event) => {
  const result = document.querySelector('.result');
  result.textContent = `You like ${event.target.value}`;
});

Result

Text input element

For some elements, including <input type="text">, the change event doesn't fire until the control loses focus. Try entering something into the field below, and then click somewhere else to trigger the event.

HTML

<input placeholder="Enter some text" name="name"/>
<p id="log"></p>

JavaScript

const input = document.querySelector('input');
const log = document.getElementById('log');

input.addEventListener('change', updateValue);

function updateValue(e) {
  log.textContent = e.target.value;
}

Result

Specifications

Browser compatibility

BCD tables only load in the browser

Different browsers do not always agree whether a change event should be fired for certain types of interaction. For example, keyboard navigation in <select> elements used to never fire a change event in Gecko until the user hit Enter or switched the focus away from the <select> (see bug 126379). Since Firefox 63 (Quantum), this behavior is consistent between all major browsers, however.

See also