No, you have not add anything into url explicitly, selected employeeID will be sent automatically to server when submit occurs.
You can add some if-then-else into your script, to recognize, if posted value of employeeID (value of selected option) is empty or not empty. When empty, you can print current version, when nonempty, you can print detail informations about selected employee.
Now I see simplicity of your question. If you require only this, you can use <form method="GET">, which is better for debugging...