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HTML

Living Standard — Last Updated 17 December 2025

1. 1. 1. 4.8.5 The iframe element
      2. 4.8.6 The embed element
      3. 4.8.7 The object element

4.8.5 The iframe element

Categories:

Flow content.

Phrasing content.

Embedded content.

Interactive content.

Palpable content.

Contexts in which this element can be used:

Where embedded content is expected.

Content model:

Nothing.

Tag omission in text/html:

Neither tag is omissible.

Content attributes:

Global attributes

src — Address of the resource

srcdoc — A document to render in the iframe

name — Name of content navigable

sandbox — Security rules for nested content

allow — Permissions policy to be applied to the iframe's contents

allowfullscreen — Whether to allow the iframe's contents to use requestFullscreen()

width — Horizontal dimension

height — Vertical dimension

referrerpolicy — Referrer policy for fetches initiated by the element

loading — Used when determining loading deferral

Accessibility considerations:

For authors.

For implementers.

DOM interface:

[Exposed=Window]
interface HTMLIFrameElement : HTMLElement {
  [HTMLConstructor] constructor();

  [CEReactions, ReflectURL] attribute USVString src;
  [CEReactions] attribute (TrustedHTML or DOMString) srcdoc;
  [CEReactions, Reflect] attribute DOMString name;
  [SameObject, PutForwards=value, Reflect] readonly attribute DOMTokenList sandbox;
  [CEReactions, Reflect] attribute DOMString allow;
  [CEReactions, Reflect] attribute boolean allowFullscreen;
  [CEReactions, Reflect] attribute DOMString width;
  [CEReactions, Reflect] attribute DOMString height;
  [CEReactions] attribute DOMString referrerPolicy;
  [CEReactions] attribute DOMString loading;
  readonly attribute Document? contentDocument;
  readonly attribute WindowProxy? contentWindow;
  Document? getSVGDocument();

  // also has obsolete members
};

The iframe element represents its content navigable.

The src attribute gives the URL of a page that the element's content navigable is to contain. The attribute, if present, must be a valid non-empty URL potentially surrounded by spaces. If the itemprop attribute is specified on an iframe element, then the src attribute must also be specified.

The srcdoc attribute gives the content of the page that the element's content navigable is to contain. The value of the attribute is used to construct an iframe srcdoc document, which is a Document whose URL matches about:srcdoc.

The above requirements apply in XML documents as well.

<article>
 <h1>I got my own magazine!</h1>
 <p>After much effort, I've finally found a publisher, and so now I
 have my own magazine! Isn't that awesome?! The first issue will come
 out in September, and we have articles about getting food, and about
 getting in boxes, it's going to be great!</p>
 <footer>
  <p>Written by <a href="/users/cap">cap</a>, 1 hour ago.
 </footer>
 <article>
  <footer> Thirteen minutes ago, <a href="/users/ch">ch</a> wrote: </footer>
  <iframe sandbox srcdoc="<p>did you get a cover picture yet?"></iframe>
 </article>
 <article>
  <footer> Nine minutes ago, <a href="/users/cap">cap</a> wrote: </footer>
  <iframe sandbox srcdoc="<p>Yeah, you can see it <a href=&quot;/gallery?mode=cover&amp;amp;page=1&quot;>in my gallery</a>."></iframe>
 </article>
 <article>
  <footer> Five minutes ago, <a href="/users/ch">ch</a> wrote: </footer>
  <iframe sandbox srcdoc="<p>hey that's earl's table.
<p>you should get earl&amp;amp;me on the next cover."></iframe>
 </article>

In the HTML syntax, authors need only remember to use U+0022 QUOTATION MARK characters (") to wrap the attribute contents and then to escape all U+0026 AMPERSAND (&) and U+0022 QUOTATION MARK (") characters, and to specify the sandbox attribute, to ensure safe embedding of content. (And remember to escape ampersands before quotation marks, to ensure quotation marks become " and not ".)

In XML the U+003C LESS-THAN SIGN character (<) needs to be escaped as well. In order to prevent attribute-value normalization, some of XML's whitespace characters — specifically U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), and U+000D CARRIAGE RETURN (CR) — also need to be escaped. [XML]

If the src attribute and the srcdoc attribute are both specified together, the srcdoc attribute takes priority. This allows authors to provide a fallback URL for legacy user agents that do not support the srcdoc attribute.

This happens without any unload events firing (the element's content document is destroyed, not unloaded).

Although iframes are processed while in a shadow tree, per the above, several other aspects of their behavior are not well-defined with regards to shadow trees. See issue #763 for more detail.