Validate data when textbox loses focus
<p>In my ASP.Net web application, there is a textbox to receive ProductId. When the user enters data into the ProductId textbox and moves to the next textbox, I want to validate the data against a table and if matching record is found, I want to display Product details in different controls (readonly and normal textboxes) else I want to display a message about "New Product" and continue. I do not want to do the verification AFTER the user enters all data and press the Save button, but it should be done immediately. I was hoping that the Web Form textbox would have a LostFocus event, but do not know how to handle the requirement.</p>
