HTML5: Edition for Web Authors

4.10.15 The output element

Categories:

Flow content.

Phrasing content.

Listed, labelable, and resettable form-associated element.

Palpable content.

Contexts in which this element can be used:

Where phrasing content is expected.

Content model:

Phrasing content.

Content attributes:

Global attributes

for

form

name

DOM interface:

interface HTMLOutputElement : HTMLElement {
  [PutForwards=value] readonly attribute DOMSettableTokenList htmlFor;
  readonly attribute HTMLFormElement? form;
           attribute DOMString name;

  readonly attribute DOMString type;
           attribute DOMString defaultValue;
           attribute DOMString value;

  readonly attribute boolean willValidate;
  readonly attribute ValidityState validity;
  readonly attribute DOMString validationMessage;
  boolean checkValidity();
  void setCustomValidity(DOMString error);

  readonly attribute NodeList labels;
};

The output element represents the result of a calculation.

The for content attribute allows an explicit relationship to be made between the result of a calculation and the elements that represent the values that went into the calculation or that otherwise influenced the calculation. The for attribute, if specified, must contain a string consisting of an unordered set of unique space-separated tokens that are case-sensitive, each of which must have the value of an ID of an element in the same Document.

The form attribute is used to explicitly associate the output element with its form owner. The name attribute represents the element's name.

output . value [ = value ]

Returns the element's current value.

Can be set, to change the value.

output . defaultValue [ = value ]

Returns the element's current default value.

Can be set, to change the default value.

output . type

Returns the string "output".

The htmlFor IDL attribute must reflect the for content attribute.

<form onsubmit="return false" oninput="o.value = a.valueAsNumber + b.valueAsNumber">
 <input name=a type=number step=any> +
 <input name=b type=number step=any> =
 <output name=o></output>
</form>