Simple total price

Can you help me? thanks <img src='https://asprunner.com/forums/file.php?topicimage=1&fieldname=reply&id=55960&image=1&table=forumreplies' class='bbc_emoticon' alt=':(' />

use can use javascript API or custom event code.
For Javascript API:

http://www.asprunner.com/forums/topic/13678-how-to-calculate-values-on-the-fly/
For Event custom code :

http://www.asprunner.com/forums/topic/14754-once-again-about-total//

Hi Romaldus, thanks for help me <img src='https://asprunner.com/forums/file.php?topicimage=1&fieldname=reply&id=55962&image=1&table=forumreplies' class='bbc_emoticon' alt=':)' />

I want use metod custom code, can you help me for insert in my code? thanks
i have look your solution:

$values["ExtendedPrice"] = ($values["UnitPrice"] $values["Quantity"]) - (($values["Discount"]/100)($values["UnitPrice"] * $values["Quantity"]));
I have not 'quantity', i have only, product field and price field.
product field price field

product 1 10,00

product 2 10,00

product 3 50,00
total 70,00

I have resolved my problem with 'Report'. Thanks <img src='https://asprunner.com/forums/file.php?topicimage=1&fieldname=reply&id=55966&image=1&table=forumreplies' class='bbc_emoticon' alt=':)' />