How do I send a command after submitting a form?


I need to do something when the user submits a form so that it sends a command to the server, :

 if($_GET("cmd")=="save")

Got to do something with the thing above,
I thought of using:

<a href="?cmd=save">Save</a>

But if I do that it will not complete the form action so:

<form action="{{ pageName }}">

Will not be executed…
So how would I fix this problem?
thanks all đŸ™‚