Why Window???

I've noticed that when I try mouse-wheel clicking (middle clicking) on the "PLAY LIVE CHESS" link, it opens a new tab (I'm using Fx3) that says "javascript:openLiveChess();".

Could you change that button to a normal link, opening a new window when you left click on it but allowing middle clicking?

That would be greatly appreciated.

P.S. I made this picture in appreciation:

That's a setting in firefox; not chess.com.

 To fix it, try going to Tools>Options>Tabs and change open links in new tab to: open links in current tab.

Or just left click on the link; it's a javascript command so it's made to be executed in the window it's found.

You don't understand how javascript command works, do you?

If I open without opening it in a new window, it's a blank page.

You telling me to left click on it and play it in the window it's found defeats the purpose of why I made this thread.

You must have misunderstood me. The javascript is meant to open a new window for the live chess page.

What I meant is that by middle clicking, you're telling firefox to open it in a new tab, which won't work.  Left clicking should open it in a new window as it is meant to do, unless you have a setting changed in the options dialogue. 
You can always just navigate manually to the url: http://live.chess.com/online/play/

What setting allows me to change it?

Open Options from the Tools menu, and click on the Tabs tab.  Set the setting, New Pages Should Be Opened In... to Current Tab or New Tab, and try again.

That will force a link that wants to open in a  new window to open in a tab or your current tab when clicked.  Middle clicking, however, will always open in a new tab.  Middle clicking the live chess button doesn't work for me either; you may just have to input the url in a new tab manually if the above fix doesn't work.