To add an event, submit your form to $forms.cartadd.action with a form method of $forms.cartadd.method. This form requires a parameter called event which contains the URL value (such as $event.url) of the event.

If not using Ajax, you can specify the return parameter which contains the URL of the page to load after the event has been added. If this omitted the user is returned to page they were on when they added the event.

Here is a sample template:

<form method="{$forms.cartadd.method}" action="{$forms.cartbulk.action}">
    <div>
        <input type="hidden" name="event" value="{$content.url|escape}" />
        <input type="submit" value="Add" />
    </div>
</form>

Additionally, the event data contains a parameter called in_cart which is true if the event is already in the user's cart, and false if not. You can use this determine whether to show add button or a remove button (removing is covered shortly).

{if $content.in_cart}
    {* show remove form or no form *}
{else}
    {* show add form *}
{/if}

Similar to adding events, you can also remove them. The only difference is that you use the $forms.cartremove.action and $forms.cartremove.method values instead.

You can use the in_cart variable once again to determine if the event is already in the cart, although if you're using the event cart rule you can assume that all events are already in the cart.

A sample template is as follows:

<form method="{$forms.cartremove.method}" action="{$forms.cartremove.action}">
    <div>
        <input type="hidden" name="event" value="{$content.url|escape}" />
        <input type="submit" value="Remove" />
    </div>
</form>

To remove all events in a user's cart, submit to the $forms.cartempty.action URL.

<form method="{$forms.cartempty.method}" action="{$forms.cartempty.action}">
    <div>
        <input type="submit" value="Remove All" />
    </div>
</form>

When using the event cart and displaying a list of all events for a user, you can also determine any clashes using the clashes array. Each element in this array has a key and value: The key is the ID field of the event it clashes with, while the value is the URL field of the preferred event.

To resolve a clash you must submit to $forms.cartclash.action. There are three required parameters: event1, event2 and preferred. The first two parameters (event1 and event2) correspond to the ID field of the two events the clash is being resolved for, while the preferred field should contain 0 for no preference, the value of event1 if the first event is preferred, or the value of event2 if the second event is preferred.

A sample template is provided with Recite for outputting clash data and resolve form.

You can bulk add or remove events using the $forms.cartbulk.action URL. This action can accept an array called add[] which contains the URL field of events to add, an array called remove[] which contains the URL field of events to remove, and a parameter called empty, which if present will empty the cart.

Events are removed prior to being added, so if the same URL is present in the remove and the add arrays then ultimately the event will be added.

There is a sample template provided with Recite which demonstrates this functionality.