Synchronous communication means one task must complete before the next task starts.
The program waits until the current process finishes.
In synchronous execution, each line waits for the previous line to complete.
If one task takes time, the entire program becomes slow.
Asynchronous communication allows tasks to run independently.
The program does not wait and continues executing other operations.
In asynchronous execution, time-consuming operations run in the background.
This keeps applications responsive and fast.
AJAX uses asynchronous communication so the browser does not freeze while waiting for server responses.
Understanding the difference between synchronous and asynchronous execution is essential before learning real AJAX implementations.