MacBook Air and LCD Projector
You can drag the title bar of the browser window over to the other display. If you open the System Preferences > Displays, then Arrangement tab, you can see where the projector's display is in relation to the laptop display. The main display (typically the laptop's) has a tiny white menu bar depicted in this Arrangement window. 

Just click-drag the window in the direction of the second display and it will pop over to the projector.

You can also change the arrangement if it helps. Put the projector above, below, left/right of your laptop display.