HTMLOutputElement: defaultValue property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since August 2016.

The defaultValue property of the HTMLOutputElement interface represents the default text content of this <output> element. Getting and setting this value is equivalent to getting and setting textContent on the <output>.

Value

A string.

Examples

In the example below, the defaultValue still returns the value originally written in the HTML. Changes to value will not affect the defaultValue or its textContent in the DOM.

html
<fieldset>
  <legend>Add two numbers</legend>
  <p>
    <input type="number" id="operand1" value="5" aria-label="First number" />
    +
    <input type="number" id="operand2" value="7" aria-label="Second number" />
    =
    <output
      id="result"
      for="operand1 operand2"
      aria-live="polite"
      aria-controls="output"
      >12</output
    >
  </p>
</fieldset>
<pre id="logs" aria-live="polite"></pre>

js
const logs = document.getElementById("logs");
const operand1 = document.getElementById("operand1");
const operand2 = document.getElementById("operand2");
const result = document.getElementById("result");

function updateResult() {
  result.value = operand1.valueAsNumber + operand2.valueAsNumber;
  logs.innerText = `result.defaultValue: ${result.defaultValue}\nresult.value: ${result.value}`;
}

operand1.addEventListener("input", updateResult);
operand2.addEventListener("input", updateResult);
updateResult();