by loren_d_c » Tue Jul 08, 2008 1:35 pm
The Custom Checkout Fields feature will not generate a JavaScript 'alert' if the required field is not provided, but it should catch this internally when the form is submitted, and instead of allowing the checkout to proceed should reload the checkout page with a message at the top telling the shopper that they didn't provide information in that required field.
Note that this error message is generated where ever the [-- ShopSiteMessages --] tag is located within the [-- DEFINE Shipping --] section of your shopping cart template, so if you are using a custom shopping cart template make sure this section contains this tag and that it is in a visible high-profile location.
If you want a JavaScript 'alert' to pop up if the shopper tries to finalize the order with this field empty, then you would have to add that check yourself via custom JavaScript added to the 'Javascript added at start of built-in CheckIt function' field in the Commerce Setup -> Order System -> Checkout menu.
-Loren