amp-dynamic-css-classes

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Introduction

AMP's dynamic CSS classes provided by the amp-dynamic-css-class tag 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>
  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-localhost) .if-localhost {
    display: none;
  }
  body:not(.amp-viewer) .if-viewer,
  body.amp-viewer .if-not-viewer {
    display: none;
  }
</style>

You do not need to include a call to the amp-dynamic-css-classes component to initialize the classes on the body element

Referrer

Using these referrer classes can allow you to conditionally include elements.

Example

You were referred here or embedded by Pinterest! I'll add a few extra "Pin It" buttons You were referred here or embedded by Twitter! I'll add a few extra Tweet buttons You were referred here or embedded by Google! I'll add a few extra Google+ buttons You came here directly! Cool :) You came here directly! Cool :)
  <span class="if-pinterest">You were referred here or embedded by Pinterest! I'll add a few extra "Pin It" buttons</span>
  <span class="if-twitter">You were referred here or embedded by Twitter! I'll add a few extra Tweet buttons</span>
  <span class="if-google">You were referred here or embedded by Google! I'll add a few extra Google+ buttons</span>
  <span class="if-ampbyexample">You came here directly! Cool :)</span>
  <span class="if-localhost">You came here directly! Cool :)</span>

  <amp-social-share type="email"
    layout="fixed"
    height="30"
    width="30"></amp-social-share>
  <amp-social-share type="twitter"
    layout="fixed"
    height="30"
    width="30"
    class="if-twitter"></amp-social-share>
  <amp-social-share type="pinterest"
    layout="fixed"
    height="30"
    width="30"
    class="if-pinterest"></amp-social-share>
  <amp-social-share type="linkedin"
    layout="fixed"
    height="30"
    width="30"
    class="if-linkedin"></amp-social-share>

Viewer

The 'viewer' classes enable Try it out on the Google AMP Viewer:

Example

Hey! You're not visiting within the context of an AMP Viewer! Ahoy! Since you're coming from a viewer, I'll reorder my social share buttons to prefer the one you prefer. Hope you like 'em!
  <span class="if-not-viewer">Hey! You're not visiting within the context of an AMP Viewer!</span>
  <span class="if-viewer">Ahoy! Since you're coming from a viewer, I'll reorder my social share buttons to prefer the one you prefer. Hope you like 'em!</span>