checkout.html

{% comment %}
  See here for getting Conversion ID and Label
  https://www.en.advertisercommunity.com/t5/AdWords-Tracking-and-Reporting/Finding-you-Google-Adwords-Conversion-ID/td-p/1119060#
{% endcomment %}
{% if first_time_accessed %}
  {% assign google_conversion_id = 123456 %}
  {% assign google_conversion_label = 'xyz789' %}
  {% assign shopify_store_country  = 'US' %}
  <script type="text/javascript">
    var google_tag_params = {
      ecomm_prodid: [{% for item in order.line_items %}'shopify_{{ shopify_store_country }}_{{ item.product.id }}_{{ item.variant.id }}'{% unless forloop.last %}, {% endunless %}{% endfor %}],
      ecomm_pagetype: 'purchase',
      ecomm_totalvalue: {{ total_price | money_without_currency | remove: ',' }}
    };
  </script>
  <script type="text/javascript">
    /* <![CDATA[ */
      var google_conversion_id = {{ google_conversion_id }};
      var google_conversion_label = {{ google_conversion_label }};
      var google_custom_params = window.google_tag_params;
      var google_remarketing_only = true;
    /* ]]> */
  </script>
  <script type="text/javascript" src="//www.googleadservices.com/pagead/conversion.js"></script>
  <noscript>
    <div style="display:inline;">
      <img height="1" width="1" style="border-style:none;" alt="" src="//googleads.g.doubleclick.net/pagead/viewthroughconversion/{{ google_conversion_id }}/?guid=ON&amp;script=0"/>
    </div>
  </noscript>
{% endif %}

remarketing.html

{%- comment -%}
  Remarketing
{%- endcomment -%}
{% assign google_conversion_id = 123456 %}
{% assign google_conversion_label = 'xyz789' %}
{% assign shopify_store_country  = 'US' %}
{%- assign primaryTemplate = template | split: '.' | first -%}
{%- case primaryTemplate -%}
  {%- when 'product' -%}
    <script type="text/javascript">
      var json_product = {{ product | json }};
      var ecomm_prodid=[];
      for(var i=0;i<json_product.variants.length;i++)
      ecomm_prodid.push(json_product.variants[i].id);

      var google_tag_params = {
        ecomm_prodid: ecomm_prodid,
        ecomm_pagetype: 'product',
        ecomm_totalvalue: parseFloat('{{ product.price | money_without_currency | remove: "," }}')
      };
    </script>
  {%- when 'collection' -%}
    <script type="text/javascript">
      var google_tag_params = {
        ecomm_prodid: '',
        ecomm_pagetype: 'category',
        ecomm_totalvalue: 0
      };
    </script>
  {%- when 'cart' -%}
    <script type="text/javascript">
      var id = new Array();
      {% for item in cart.items %}
        id.push('{{ item.variant.id }}');
      {% endfor %}
      var google_tag_params = {
        ecomm_prodid: id,
        ecomm_pagetype: 'cart',
        ecomm_totalvalue: parseFloat('{{ cart.total_price | money_without_currency | remove: "," }}')
      };
    </script>
  {%- when 'search' -%}
    <script type="text/javascript">
      var google_tag_params = {
        ecomm_prodid: '',
        ecomm_pagetype: 'searchresults',
        ecomm_totalvalue: 0
      };
    </script>
  {%- when 'index' -%}
    <script type="text/javascript">
      var google_tag_params = {
        ecomm_prodid: '',
        ecomm_pagetype: 'home',
        ecomm_totalvalue: 0
      };
    </script>
  {%- else -%}
    <script type="text/javascript">
      var google_tag_params = {
        ecomm_prodid: '',
        ecomm_pagetype: 'other',
        ecomm_totalvalue: 0
      };
    </script>
{%- endcase -%}
<script type="text/javascript">
  /* <![CDATA[ */
    var google_conversion_id = {{ google_conversion_id }};
    var google_conversion_label = {{ google_conversion_label }};
    var google_custom_params = window.google_tag_params;
    var google_remarketing_only = true;
  /* ]]> */
</script>
<script type="text/javascript" src="https://www.googleadservices.com/pagead/conversion.js"></script>
<noscript>
  <div style="display:inline;">
   <img height="1" width="1" style="border-style:none;" alt="" src="https://googleads.g.doubleclick.net/pagead/viewthroughconversion/{{ google_conversion_id }}/?value=0&amp;guid=ON&amp;script=0"/>
  </div>
</noscript>