To get the Promo Code when the recalc function runs on the shopping cart page, do the following steps.1. Create Client script that is deployed on the Sales Order and will get the promo code on function 'recalc'.
2. Show the promo code on the shopping cart by : Setup>Website > Setup Website> Appearance tab> Shopping Cart > Check on 'Show Extended Cart'.
3. Create a valid promotional code to be applied.
4. Go to website and select Items.
5. On shopping cart, type in the promo code and click Apply button.
Checked on the script execution log and was able to get the promo code after the apply button was clicked.