AMP
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amp-dynamic-css-classes

Introduction

AMP's dynamic CSS classes provided by the amp-dynamic-css-class enable boolean logic for a handful of conditions

Setup

Include the amp-dynamic-css-classes extended component.

<script async custom-element="amp-dynamic-css-classes" src="https://cdn.ampproject.org/v0/amp-dynamic-css-classes-0.1.js"></script>

For the purpose of this sample, we're creating some helper CSS classes that use the CSS rules defined by amp-dynamic-css-classes. These allow us to more succinctly refer to the conditions in our code below.

<style amp-custom>
  :root {
    --space-2: 1rem;   /* 16px */
  }
  body:not(.amp-referrer-pinterest-com) .if-pinterest,
  body:not(.amp-referrer-ampbyexample-com) .if-ampbyexample,
  body:not(.amp-referrer-google-com) .if-google,
  body:not(.amp-referrer-twitter-com) .if-twitter,
  body:not(.amp-referrer-linkedin-com) .if-linkedin,
  body:not(.amp-referrer-localhost) .if-localhost {
    display: none;
  }
  body:not(.amp-viewer) .if-viewer,
  body.amp-viewer .if-not-viewer {
    display: none;
  }
  .dynamic-css {
    padding: var(--space-2);
  }
</style>

Referrer

Using these referrer classes can allow you to conditionally include elements. You do not need to include a call to the amp-dynamic-css-classes component to initialize the classes on the body element.

You were referred here or embedded by Pinterest!
You were referred here or embedded by Twitter!
You were referred here or embedded by Google!
You came here directly! Cool :)
You came here directly! Cool :)
<div>
  <div class="if-pinterest dynamic-css">You were referred here or embedded by Pinterest!</div>
  <div class="if-twitter dynamic-css">You were referred here or embedded by Twitter!</div>
  <div class="if-google dynamic-css">You were referred here or embedded by Google!</div>
  <div class="if-ampbyexample dynamic-css">You came here directly! Cool :)</div>
  <div class="if-localhost dynamic-css">You came here directly! Cool :)</div>
</div>

Viewer

The 'viewer' classes enable you to style the page based on whether it's embedded inside an AMP viewer. Try it out on the Google AMP Viewer. Note this works only on a mobile device or in your browser's mobile emulation mode.

Hey! You're not visiting within the context of an AMP Viewer!
Ahoy! Since you're coming from a viewer.
<div>
  <div class="if-not-viewer dynamic-css">Hey! You're not visiting within the context of an AMP Viewer!</div>
  <div class="if-viewer dynamic-css">Ahoy! Since you're coming from a viewer.</div>
</div>
Need further explanation?

If the explanations on this page don't cover all of your questions feel free to reach out to other AMP users to discuss your exact use case.

Go to Stack Overflow
An unexplained feature?

The AMP project strongly encourages your participation and contributions! We hope you'll become an ongoing participant in our open source community but we also welcome one-off contributions for the issues you're particularly passionate about.

Edit sample on GitHub