Javascript: dynamic global variable

I have a global variable that looks like this:

var socket_x = 'whatever';

The fact is that "x" will depend on the user's session. Let them say that the user ID is 123, I want the global variable to be:

var socket_123 = 'whatever';

Thus, each user view will have its own set of sockets as a global variable.

I just don't know how to do this.

I know I can use:

eval('socket_' + userId)   = 'whatever'; //not recommended
window['socket_' + userId] = 'whatever'; //best

but if I want to declare a global variable like this, it will not work:

var eval('socket_' + userId) = 'whatever';

Can someone help me on this?

Thank.

PS: I know that "eval" should not be used for this, but it is just for illustration.

EDIT:

Thanks for your answer, all of you, but it just doesn't work.

, ( , , php javascript):

var socket_<?php echo $_SESSION['user_id'];?> = io.connect( 'http://pubsub.pubnub.com', pubnub_setup_private );

, :

window['socket_'+actual_user_id]= io.connect( 'http://pubsub.pubnub.com', pubnub_setup_private );

.

, :

eval('socket_'+actual_user_id).emit( 'all', msg_all );

, :

window['socket_'+actual_user_id].emit( 'all', msg_all );

, 2 :

• , eval .
• eval , . , "var" , "var" , eval .

, eval, , .

PS: .