When I do a customer search, it brings up a modal dialog to display the search results.

How do I suppress the modal dialog display if I need to validate search input? That means the modal dialog will only display after validating the search input.

How is the modal box getting triggered, are you doing it using toggle control , or using Javascript ?
Also what kind of validation do you need, will a javascript validation suffice ?

My guess is you are using toggle control - if you change the code to open the Model Box through Javascript, you can finish the validation on ‘onClick’ and then based on the result you can open the modal box.

If you want server side validation i.e. validating customer data from a DB, you would have to use aync controls to send it to the server , validate and based on the result , you can conditionally trigger the modal box.