Iframe (Inline Frame) and Object elements are two distinct methods for embedding content in HTML. They can both be used to embed content such as videos, audio, PDF documents, and other web pages, but there are key differences between them.

Iframe:

• Definition: Iframe is an HTML element that embeds another independent HTML document within the current HTML document.

• Use Cases: Typically used for embedding third-party content, such as maps and videos.

• Advantages:

  • Isolation: Content within an Iframe is isolated from the parent page and has its own Document Object Model (DOM).
  • Security: Different levels of restrictions can be applied to the embedded page using the sandbox attribute to enhance security.
  • Flexibility: Iframes can responsively adjust their size to fit various viewports.

Object:

• Definition: Object is an HTML element used to embed diverse multimedia content, including Flash, PDF, and Java applets.

• Use Cases: Typically used for embedding plugin-based content that requires specific application support.

• Advantages:

  • Type Support: Supports different data types by specifying MIME types via the type attribute.
  • Fallback Content: Provides alternative content if the browser does not support the Object tag or fails to load the content.
  • Flexibility: Object elements support parameter configuration for the embedded object using <param> tags.

Examples:

Iframe Example:

html
<iframe src="https://www.example.com" width="600" height="400">
  <p>Your browser does not support iframes.</p>
</iframe>

In this example, an external webpage is embedded into the current page with specified width and height.

Object Example:

html
<object data="file.pdf" type="application/pdf" width="300" height="200">
  <a href="file.pdf">Download PDF</a>
</object>

In this example, a PDF file is embedded into the webpage. If the browser does not support direct PDF display, users can download the PDF via the provided link.

Conclusion:

Choosing between Iframe and Object primarily depends on the content type and requirements for isolation and control. Iframes are highly practical for embedding other HTML documents (such as YouTube videos), while Object is more commonly used for embedding content requiring specific plugin support.

Another reason for using iframe is the object element, where the object resource (when

The iframe element features the 'sandbox' attribute, which may prevent pop-ups and other related actions.

One reason to use the object element instead of iframe is that the object element automatically adjusts the embedded content to fit its own dimensions. Notably, in Safari on the iPhone 4s, where the screen width is 320px, the HTML content embedded via the URL may specify larger dimensions.

<iframe>

The <iframe> element represents a nested browsing context. HTML 5 Standard - "The <iframe> element"

It is primarily used for embedding resources from other domains or subdomains, but it can also be used for resources from the same domain. The advantage of <iframe> is that the embedded code is "live" and can communicate with the parent document.

<embed>

The <embed> element provides an integration point for external (typically non-HTML) applications or interactive content. (HTML 5 Standard - "The <embed> element")

Standardized in HTML 5, it was previously a non-standard tag. All major browsers implement it. Behavior before HTML 5 may have differed.

It is used for embedding browser plugins. SVG and HTML are exceptions, as they are handled differently according to the standard.

The details of what embedded content can and cannot do depend on the relevant browser plugins. For SVG, you can access the embedded SVG document from the parent using:

javascript
svg = document.getElementById("parent_id").getSVGDocument();

From within the embedded SVG or HTML document, you can access the parent using:

javascript
parent = window.parent.document;

For embedded HTML, it is not possible to access the embedded document from the parent document (as I found).

<object>

The <object> element can represent external resources, which are treated as images, nested browsing contexts, or external resources handled by plugins, depending on the resource type. (HTML 5 Standard - "The <object> element")

Conclusion

Unless you are embedding SVG or static content, it's best to use <iframe>. For SVG, use <embed> (if I'm not mistaken, <object> does not allow scripting†). Honestly, I don't know why you would use <object> unless for older browsers or Flash (which I don't use).

† As noted in the comments below, scripts within <object> will run, but the parent and child contexts cannot communicate directly. With <embed>, you can access the child context from the parent and vice versa. This means you can use scripts in the parent to manipulate the child, etc. This is not possible with <object> or <iframe>; you must set up other mechanisms, such as the JavaScript postMessage API.