AMP: Building Accelerated Mobile Pages

Using CLIENT_ID to identify a shopping cart

To get the CLIENT_ID to the server, we can just add it as a hidden field in our form like this:

<input name="client_id"        type="hidden"        value="CLIENT_ID(cart)"        data-amp-replace="CLIENT_ID">

The main things to note here are the following:

• CLIENT_ID(cart): The CLIENT_ID variable behaves like a function, and we have to pass in an argument as the namespace for the variable. We used cart here.
• data-amp-replace: This attribute is required for certain variables, including CLIENT_ID. Without it, AMP won't perform the required substitution.

If you inspect the DOM in developer tools as you submit the form, you should see that a value has been substituted, and the hidden field will look something like this: ...