1.Cross browser Compactability
New browsers and patches are released all of the time, and support for older browsers is an ongoing task. JQuery provides consistent browser functionality and lets developers focus on building functionality.
2.Cross language compactability
3.Faster development time
The amount of JQuery functions that already exist is massive and growing by leaps and bounds every day. This large base means that developers can put together UI functionality much faster and focus on the underlying business logic.
4.Low learning curve
5.Good CSS interaction