Hii all, Can we display alert box using Suitelet (POST) method ? Anyone has idea about this, let me know please.

Please elaborate, what are you trying to do?

When we click on submit button, that time show alert message, if user cannot select at least one line from the sublist using Suitelet Script.

@Yogita Kyatam I think what you can do is: In your Suitelet have a client script attached using clientScriptModulePath in the save record function trigger return true if OK otherwise alert() or use N/ui/message module to display your message as a banner and then return false