By default the calendar is disabled in Avalanche to remove bloated code. Most store owners don’t need this functionality so we’ve left it up to you to enable it manually. It’s very easy to do. You’ll need to edit two files to get the calendar working properly:
In catalog.xml you’ll need to uncomment the following lines (search in the file):
<action method="addJs"><script>calendar/calendar.js</script></action> <action method="addJs"><script>calendar/calendar-setup.js</script></action>
<block type="core/html_calendar" name="html_calendar" as="html_calendar" template="page/js/calendar.phtml"/>
Preferably do this for both catalog and product pages so you’ll also fix the calendar in Quick View.
Once you uncomment these lines throughout catalog.xml you’ll notice the calendar window works but it might not display correctly. You’ll need to copy some CSS from one of the calendar CSS files and add it to your custom.css file for Avalanche. For example: