Bootstrap/site/content/docs/4.3/utilities/embed.md

---
layout: docs
title: Embeds
description: Create responsive video or slideshow embeds based on the width of the parent by creating an intrinsic ratio that scales on any device.
group: utilities
toc: true
---

## About

Rules are directly applied to `<iframe>`, `<embed>`, `<video>`, and `<object>` elements; optionally use an explicit descendant class `.embed-responsive-item` when you want to match the styling for other attributes.

**Pro-Tip!** You don't need to include `frameborder="0"` in your `<iframe>`s as we override that for you.

## Example

Wrap any embed like an `<iframe>` in a parent element with `.embed-responsive` and an aspect ratio. The `.embed-responsive-item` isn't strictly required, but we encourage it.

{{< example >}}
<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="https://www.youtube.com/embed/zpOULjyy-n8?rel=0" allowfullscreen></iframe>
</div>
{{< /example >}}

## Aspect ratios

Aspect ratios can be customized with modifier classes. By default the following ratio classes are provided:

{{< highlight html >}}
<!-- 21:9 aspect ratio -->
<div class="embed-responsive embed-responsive-21by9">
  <iframe class="embed-responsive-item" src="..."></iframe>
</div>

<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="..."></iframe>
</div>

<!-- 4:3 aspect ratio -->
<div class="embed-responsive embed-responsive-4by3">
  <iframe class="embed-responsive-item" src="..."></iframe>
</div>

<!-- 1:1 aspect ratio -->
<div class="embed-responsive embed-responsive-1by1">
  <iframe class="embed-responsive-item" src="..."></iframe>
</div>
{{< /highlight >}}

Within `_variables.scss`, you can change the aspect ratios you want to use. Here's an example of the `$embed-responsive-aspect-ratios` list:

{{< highlight scss >}}
$embed-responsive-aspect-ratios: (
  (21 9),
  (16 9),
  (4 3),
  (1 1)
) !default;
{{< /highlight >}}