Setting Client Flags

[Emera]

I am currently constructing a simple class selection system, and I am going to store the class information using the players flags. I want to be able to select a row from a text list and apply the class to the player by pressing a GUI button. I am having some difficulties. It won't set the flag. Can anybody help out?

PHP Code:

function Class_Button1.onAction() {
  client.class = Class_TextList1.selectedrow;
} 


Thank you for your help.
If there is any other way to store information for a player other than client flags, please let me know. I have heard of clientr flags and was wondering what they were. I did some research and I see they can only be read clientside and applied to the player serverside. I am using client flags for the time being though.

I have a suspicion that the problem occurring lies here.

PHP Code:

Class_TextList1.selectedrow;