I have three five text boxes in my page.

Part No, Description, Quantity, Unit Price and Total Cost.

If the Part Number is not empty I want post back on Quanity, so that it will calculate the Total Cost.

If the Part Number is empty (non-inventory part), then I don't want post back on quantity as I will calculate the price when they enter the unit price (AutoPostBack in Unit Price field).

Could you please help me how to do this? Or is there a way to do this using client-side script?

Thanks,
Smitha