Dynamically change placeholder of a checkout field

[ramonabadescu]

Hello, I would like to dynamically change the placeholder for the "City" field at checkout when a user selects a certain zone. For example, if a user selects "Zone 1," I want the placeholder to show "City X." If the person selects "Zone 2," the placeholder should be "City Y," and so on.

Thanks in advance for any advice!