How to track some one using GPS and display on my google map

Question

Hi Friends,

I m already Done application of google map,that is works on pincode base
stored lat,long in database and display markers depends user choosing location

I.e


Selecte State:Dropdown (Tamil Nadu)

Select District:Dropdown (Chennai)


Show(Button)


Depends on the selection the marker ll show it.


Now My client ask to track his sales person particular time like A to B destination How to make that ??