I’m booking a flight, but once I get to the ‘Choose a Seat’ page, there are no seats available. Does this mean I will be placed on standby?

[sanakhan]

No Seats Available at Booking: Will You Be Placed on Standby?
It can be alarming to reach the seat selection screen and see no available seats. This doesn't necessarily mean you're not confirmed. Some airlines don't release all seats during booking, or they may be assigning seats at the gate. You’re not on standby unless the confirmation explicitly says so.
For more clarification:

 

[Willjack]

Not necessarily—if you see no seats available during booking, it usually means all pre-selectable seats are taken, but you still have a confirmed ticket. The airline may assign your seat at check-in or at the gate. It doesn’t mean you're on standby unless your ticket specifically says so. Just check in as early as possible to improve your chances of getting a good seat!